PubMed Health⌕ Search

Biomedical subjects

J Baer

Publications and source records attributed to J Baer.

At least 19 recordsLinked to original sources
PubMed2000

Interactive multimedia preventive alcohol education: a technology application in higher education.

This article summarizes the process of implementation and short-term impact on knowledge and attitudes of an interactive multimedia software program on preventive alcohol education for young adults. The three factors related to behavioral change addressed in the software are self-efficacy in maintaining personal control and safety while using alcohol, attitudes and related expectations regarding the physiological and behavioral consequences of alcohol consumption, and peer norms regarding alcohol consumption. As compared to alternative alcohol education and a no-alcohol education groups, students using the interactive computer lesson reported learning more about dose-response and ways to intervene with friends in peril. The article concludes with consideration of the import of this technology for informing students about the consequences of alcohol use, and the utility to higher education institutions of using this technology in an era when pressures increase for due diligence around student safety but with few additional institutional resources.

Adaptation, Psychological↗
PubMed1999

The effects of family structure and SES on family processes in early adolescence.

This study investigates parent-adolescent relationships in early adolescence, focusing on the effects of dyadic communication, family cohesion, family structure, and SES on family conflict in three ethnic groups: African-American (n =1886), Mexican-American (n =2657), and Euro-American (n =3052). Sixth, seventh and eighth grade girls and boys completed questionnaires and results were analysed using independent samples t -tests and multiple regression. Results showed 3-year increases in family conflict in all three ethnic groups. There were significant differences in scale scores on conflict, communication, and family cohesion between nuclear and single-parent families. Some ethnic and gender differences were also found. Discussion focuses on the implications of the findings for family life.

Adolescent↗
PubMed1998

Exercised-induced increase in lipid peroxidation parameters in amenorrheic female athletes.

OBJECTIVE: To determine plasma lipid peroxidation parameters in eumenorrheic and amenorrheic athletes and to evaluate differences in their response to exercise-induced oxidative stress. In female athletes, intense physical exercise has been shown to be associated with an increased occurrence of menstrual dysfunction with lower levels of E2. Recently, a protective role has been demonstrated for estrogens as free radical scavengers. DESIGN: Comparison of eumenorrheic and amenorrheic athletes before and after an acute bout of exercise. SETTING: Academic Research Environment. PATIENT(S): Seven eumenorrheic (normally menstruating) and seven amenorrheic (<3 menses/year) female athletes aged 18 to 35 years participating in regular training. MAIN OUTCOME MEASURE(S): Plasma and low-density lipoprotein oxidation parameters, plasma E2 and vitamin E levels, and creatine kinase activity. RESULT(S): Both the amenorrheic and eumenorrheic athletes demonstrated a significant decrease in the lag time of conjugated diene formation after exercise (P < 0.01), with greater magnitude of change occurring in the amenorrheic athletes (P < 0.05). In addition, postexercise samples from amenorrheic (but not eumenorrhic) athletes showed a significant (P < 0.01) increase in oxysterol formation as compared to baseline values. Amenorrheic athletes also demonstrated a significantly higher baseline creatine kinase activity and a nonsignificant (P = 0.04) trend of an increase in creatine kinase activity after exercise. CONCLUSION(S): The results of this study shows that amenorrheic female athletes demonstrate an increased potential for lipid peroxidation after exercise. This could be related to lower plasma E2 levels in this group, considering the strong free radical scavenging ability of estrogens identified recently.

Adolescent↗
PubMed1998

Interdisciplinary health care and female victims of domestic violence.

Female victims of domestic violence often face uncertainty in hospital emergency rooms. Victims may encounter physicians, nurses, social workers, and other health care providers who do not work collaboratively, have limited knowledge of domestic violence, and express negative attitudes. Hence, treatment outcomes may be negative. A retrospective case study of 153 medical records of female victims at two Midwestern hospital emergency medicine departments was completed. Findings suggest positive treatment outcome where interdisciplinary collaboration was evident. Included were more accurate assessments in terms of past history, more descriptive emotional symptoms displayed by victims, and written documentation of recommendations concerning intervention and linkage to community resources. Implications for policy and interdisciplinary training are discussed.

Adolescent↗
PubMed1996

Pharmacokinetic evaluation of high-dose etoposide phosphate after a 2-hour infusion in patients with solid tumors.

Etoposide phosphate, a water soluble prodrug of etoposide, was evaluated at levels potentially useful in transplantation settings in patients with malignancies. For pharmacokinetic studies of etoposide phosphate in this phase I study, 21 patients with solid tumors were treated with etoposide phosphate given as etoposide equivalents of 250, 500, 750, 1000 and 1200 mg/m2 infused over 2 h on days 1 and 2, and G-CSF 5 micrograms/kg per day starting on day 3 until WBC was > or = 10,000/microliters. Qualitative, quantitative, and pharmacokinetic analysis was performed as reported previously. Rapid conversion of etoposide phosphate into etoposide by dephosphorylation occurred at all dosage levels without indication of saturation of phosphatases. Plasma levels (C(pmax)) and area under the curve (AUC) of etoposide phosphate and etoposide demonstrated linear dose effects. For etoposide, plasma disposition demonstrated biphasic clearance, with mean T1/2 alpha of 2.09 +/- 0.61 h, and T1/2 beta of 5.83 +/- 1.71 h. An AUC as high as 1768.50 micrograms.h/ml was observed at a dose of 1200 mg/m2. The total body clearance (TBC) showed an overall mean of 15.72 +/- 4.25 ml/min per m2, and mean volume of distribution (VDss) of 5.64 +/- 1.06 l/m2. The mean residual time (MRT) for etoposide was 6.24 +/- 1.61 h. In urine, etoposide but not etoposide phosphate, was identified with large quantitative variations (1.83% to 33.45% of injected etoposide equivalents). These results indicate that etoposide phosphate is converted into etoposide with the linear dose-related C(pmax) and AUCs necessary for use of this agent at the high dosage levels needed in transplantation protocols. A comparison of pharmacokinetic parameters of high-dose etoposide with the values observed in our study with etoposide phosphate revealed comparable values for the clinically important C(pmax) and AUCs, clearance, terminal T1/2 and MRT. In contrast to the use of etoposide, etoposide phosphate can be delivered in aqueous vehicles and therefore may offer the advantage of ease of administration.

Antineoplastic Agents↗
PubMed1996

Depletion of glutathione from brain cells in hyponatremia.

In response to hyponatremia, brain cells extrude electrolytes and organic osmolytes, thereby minimizing brain edema. We demonstrate that rat brain is depleted of the antioxidant glutathione in response to hyponatremia and that osmotically-induced loss of glutathione makes neuronal cells more susceptible to oxidative injury. Total glutathione content of brain tissue decreased from 6.80 +/- 0.14 mumol/g dry wt in normonatremic controls to 5.00 +/- 0.31 mumol/g dry wt after 72 hours of hyponatremia. Following slow correction of hyponatremia, brain glutathione content returned to control values (6.77 +/- 0.34 mumol/g dry wt). Brain content of taurine, a beta-amino acid with antioxidant properties, similarly decreased in hyponatremia (29.6 +/- 0.9 to 17.1 +/- 1.2 mumol/g dry wt), then increased with slow correction (24.8 +/- 1.3 mumol/g dry wt). Although taurine served as an osmolyte in rat heart, liver and brain, osmotically-induced changes in glutathione content were found only in brain. We also studied osmotically-induced changes in glutathione and taurine content in C6 glioma and SK-N-SH neuroblastoma cells. In both cell lines, adaptive decreases in glutathione and taurine content were found in response to lowering medium sodium concentration from 140 mM to 100 mM. The cell content of these solutes increased after returning to media containing 140 mM sodium. Following exposure of both cell lines to hypoosmolar media, there was no increase in media content of glutathione. This suggest that osmotic depletion of glutathione is not due to cellular efflux of intact glutathione. We questioned if osmotic depletion of glutathione and taurine renders brain cells more susceptible to oxidative stress. Incubation of SK-N-SH cells with 1.0 mM H2O2 for four hours induced greater cytolytic injury in cells adapted to hypoosmolar media than in isoosmolar controls. Hypoosmolar C6 glioma cells were not significantly more sensitive to cytolytic injury from H2O2 than were cells grown in isosmolar media. We conclude that hypoosmolality induces glutathione depletion in rat brain in vivo and in cultured brain cells in vitro. Osmotic depletion of this antioxidant renders SK-N-SH neuronal cells more susceptible to oxidative injury.

Animals↗
PubMed1995

MR urography: technique and application.

PURPOSE: To evaluate a magnetic resonance (MR) technique for depicting the kidneys and urinary tract. MATERIALS AND METHODS: Fourteen patients with urinary tract obstruction and 20 without obstructions were examined with a modified, heavily T2-weighted fast spin-echo pulse sequence (MR urography). In addition, six healthy volunteers underwent modified MR urography with intravenous administration of furosemide and ureteral compression prior to imaging. RESULTS: MR urography provided high-resolution images of the kidneys and urinary tract in all patients with obstruction with intact collecting systems. Anatomic anomalies were depicted in two patients. Intraluminal neoplasia was well demonstrated in both obstructed and nonobstructed systems (n = 4). Furosemide-enhanced MR urography provided fine anatomic and functional detail of both the kidneys and urinary tract (n = 6). CONCLUSION: MR urography may provide an alternative to more conventional urinary tract imaging techniques. It does not require ionizing radiation or iodinated contrast material. When combined with furosemide and ureteral compression, MR urography provides fine detail and reflects function.

Adult↗
PubMed1995

Dyspnea in dystonia. A functional evaluation.

BACKGROUND: Dystonia consists of action-triggered sustained focal muscle contractions, worsened by effort, and resulting in voice changes, abnormal posturing, and dyspnea. The cause of dyspnea, previously unexplained, is the basis of this report. METHODS: Since the maximal efforts required to perform pulmonary function testing (PFT) could worsen the muscular contractions in dystonic patients, we used several tests to identify possible causes of dyspnea. These included spirometry with flow volume loops (FVL), tidal volume breathing, maximum voluntary ventilation (MVV), and inspiratory and expiratory muscle pressures (PImax, PEmax), sitting and supine. We used cycle ergometry with arterial blood gas (ABG) values to detect cardiac/pulmonary limitations and respiratory inductive plethysmography (RIP) to assess chest wall/abdominal movements for synchrony. Dynamic videofluoroscopy (VF) assessed and recorded the action-triggered muscle activity of the upper airways and the diaphragm during quiet breathing, speech, swallowing, and maximal respiratory maneuvers similar to the efforts required during PFT. RESULTS: Twenty-six dystonic patients, 12 women and 14 men, ages 14 to 70 years (mean age, 52.3 years) were evaluated. Their neurologic classification included 22 primary (idiopathic) and 4 secondary (2 postneuroleptic use, 2 posstraumatic). Four patients originally classified as having focal dystonia had dyspnea and were found to have diaphragmatic and/or upper airway dysfunction too. The PFTs showed abnormal FVL and/or tidal volume breathing patterns, with intermittent interruptions of air flow during inspiration or expiration in 20 of 24 patients. The VF was abnormal in 24 of 26 patients: 19 patients had combined upper airway (UA) and diaphragmatic dysfunction (DD); 1 patient had UA dysfunction alone, and 4 patients had DD alone. Except for poor effort and/or dystonic movements, cycle ergometry was normal in 18 of 21 patients. The ABG values and/or pulse oximetry were normal in 19 of 22 patients. CONCLUSION: Dyspnea in dystonia appears to be due to excessive and/or dysynchronized contractions of the upper airways and/or diaphragm, with usually normal gas exchange. These spasmodic and irregular muscular contractions during speech and daily activities are associated with the sensation of excessive effort to overcome the spasms. Excessive spasms can be triggered during PFT and are best detected on FVL patterns coupled with dynamic VF.

Adolescent↗
PubMed1995

An evaluation of the reliability of Widmark calculations based on breath alcohol measurements.

This study evaluated the reliability of Widmark calculations, based on breath ethanol reading (BrACs), for estimating the amount of alcohol consumed. A standard ethanol dose (males 0.51 g/kg; females 0.43 g/kg) was given to 115 college seniors, and BrACs were measured for two hours. Calculations of ethanol dose were performed using BrACs taken at 60, 75, 105, and 125 minutes after drinking. Mean calculated ethanol doses were lower than actual doses at each time point (P < 0.001). Mean underestimates were 13, 12, 15, and 14 mL of 100 proof vodka at 60, 70, 105, and 125 min after drinking. Calculated doses overestimated actual doses in 11, 10, 3, and 3 subjects at 60, 75, 105, and 125 min after drinking. The maximum overestimates were 13, 11, 6, and 8 mL of vodka at 60, 75, 105, and 125 min after drinking. At the 95% confidence level, the calculated dose at 105 and 125 min did not overestimate the true dose, but could underestimate it by as much as 30 mL vodka.

Adult↗
PubMed1993

Organic osmolytes in acute hyponatremia.

The defense of brain volume during hyponatremia cannot be explained by the losses of brain sodium and potassium. We have examined the brain losses of organic osmolytes in rats after 24 h of severe hyponatremia induced by the administration of vasopressin and 5% dextrose in water. Normonatremic controls and animals with intermediate plasma sodium concentration ([Na]) were produced in vasopressin-treated animals by the administration of isocaloric gavages containing varying amounts of NaCl and free water. The animals were killed at 24 h by decapitation, and one brain hemisphere was quickly frozen in liquid nitrogen for organic osmolyte determinations. When compared with controls (plasma [Na] = 139 +/- 1.5 mM), hyponatremic animals (plasma [Na] = 96 +/- 1 mM) had significantly reduced brain contents for sodium, potassium, chloride, glutamate, myo-inositol, N-acetylaspartate, aspartate, creatine, taurine, gamma-aminobutyric acid, and phosphoethanolamine. Plasma [Na] was highly correlated (P < 0.001) with the brain contents for sodium, potassium, and organic osmolytes. Whereas the observed increase in brain water during hyponatremia was only 4.8%, by calculation, brain swelling without brain organic osmolyte losses would have been 11%, an amount that jeopardizes survival.

Acute Disease↗
PubMed1992

Epitope mapping of Streptococcus mutans SR protein and human IgG cross-reactive determinants, by using recombinant proteins and synthetic peptides.

alpha-Hemolytic oral streptococci are known to possess a family of cell surface cross-reactive proteins termed Ag I/II, having a molecular mass of approximately 180 to 210 kDa. These proteins are implicated in bacterial adherence to various oral tissues, and we showed recently that the SR protein, an I/II Ag-related protein, from Streptococcus mutans OMZ 175 serogroup f possesses Ag mimicry with human IgG. In this study, regions of the SR protein encoding the cross-reactive epitope(s) were analyzed by expressing selected restriction fragments from the cloned sr gene. The three SR-derived polypeptides reacted in ELISA with anti-SR rabbit IgG, whereas only the two polypeptides located along the carboxyl-terminal two thirds of the SR protein reacted with anti-human IgG rabbit IgG. In order to locate more precisely the human IgG-cross-reactive region, we synthesized six peptides, on the basis of the recently determined complete nucleotide sequence of the sr gene. Among these peptides, peptide 2, corresponding to the alanine-rich repeating amino-terminal region, peptide 3, located in the three tandem proline-rich regions, and peptide 6, located near the cell wall-spanning region, were the most interesting in term of antigenicity and immunogenicity. Anti-peptide 2, 3, and 6 rabbit IgG reacted with free SR and with cell wall-associated SR. Peptide 1, located near the amino terminus, was poorly immunogenic. Peptides 4 and 5, located in the putative human IgG-cross-reactive region, were immunogenic; however, anti-peptide 4 rabbit IgG reacted only weakly with SR or human IgG, whereas anti-peptide 5 rabbit IgG reacted strongly with SR and human IgG, and peptide 5 was recognized by anti-SR and anti-human IgG rabbit IgG. These results confirm the cell surface accessibility of this epitope and its potential participation in eliciting, in rabbits, anti-SR IgG cross-reactive with human IgG.

Amino Acid Sequence↗
PubMed1992

Interferon-alpha suppresses the capacity of T cells to help antibody production by human B cells.

This study was designed to analyze the effect of interferon-alpha (IFN-alpha) on the potential of T cells to help B-cell differentiation in vitro. Human splenic T cells preactivated via the T-cell receptor (TCR)/CD3 complex, as well as murine EL4 thymoma T cells preactivated with phorbol esters, stimulated human B cells via a species cross-reactive physical interaction to differentiate into antibody-producing cells. If the human or murine T cells were activated in the presence of IFN-alpha, normal proliferation and interleukin-2 (IL-2) production occurred, but the cells did not acquire any B-cell helper potential. Therefore, IFN-alpha modulates the B-cell stimulatory potential of T cells by interfering with the T-cell activation process. In contrast, IFN-alpha neither acted on B cells directly nor on already activated T cells, because it did not suppress B-cell differentiation induced by T cells preactivated in the absence of IFN-alpha. IFN-alpha did not induce the production of inhibitory T-cell factor(s), since T cells preactivated in the presence of IFN-alpha did not inhibit the interaction of B cells with T cells optimally preactivated in the absence of IFN-alpha. Taken together the data indicate that IFN-alpha suppresses the potential of T cells to stimulate B-cell differentiation by interfering with the T-cell activation process, but acts neither on B cells directly nor on already activated T cells.

Animals↗
PubMed1991

Cytotoxicity and activation of CB1954 in a human tumour cell line.

CB1954 (5-aziridin-1-yl-2,4-dinitrobenzamide) is a monofunctional alkylating agent, to which Walker 256 cells are very sensitive. These cells express a nitroreductase which reduces CB1954 to a bifunctional crosslinking agent 5-(aziridin-1-yl)-4-hydroxylamino-2-nitrobenzamide. In vitro testing on the human colon line LS174T showed that the differential cytotoxicities between the monofunctional agent (CB1954), and the active species (generated in situ by the addition of NADH and the Walker rat nitroreductase) were smaller than anticipated due to the unexpected toxicity of CB1954 (IC50 value for CB1954 on LS174T cells of 78 microM). The toxicity of the chemically synthesised active form was less than if it had been generated in situ (on LS174T cells). Further experiments showed that NADH was toxic at the levels used to generate the active species (500 microM). Gel filtration and electrophoresis experiments demonstrated that the human colon carcinoma and choriocarcinoma cell lines MAWI and JAR, as well as LS174T express an enzyme of similar molecular weight to that of the 33 kD Walker cell nitroreductase, which is capable of reducing CB1954 to its toxic metabolite, and reducing MTT to its insoluble formazan salt. The expression of this enzyme presumably accounts for the unexpected toxicity of CB1954.

Animals↗
PubMed1991

Behavioral development and maternal care in tufted capuchins (Cebus apella) and squirrel monkeys (Saimiri sciureus) from birth through seven months.

Fourteen infant capuchins and eight squirrel monkeys reared by their mothers in captive species-typical social groups were observed from birth through 7 months. Motoric altriciality of the neonatal capuchin relative to the squirrel monkey is a key feature of behavioral differences between the species in the first few months after birth. Infants of the two species differed substantially in age at onset of independent locomotion, the developmental profile of independent activities, and the overall amount and rate of particular social activities. Capuchins displayed a lag of 7 weeks relative to squirrel monkeys in the pattern of increasing time spent alone; lags in other indices of independent activity and exploratory behaviors were also evident, although not as clear-cut. The species also differed substantially in the nature and frequency of social interactions between infants and others. Capuchins, especially later-born infants of multiparous mothers, experienced a more socially interactive infancy than squirrel monkeys. Contrasts in behavioral developmental and infant care in the two species are related to the timing and duration of the weaning process.

Age Factors↗
PubMed1991

Colonic diverticulitis in young patients with chronic renal failure and transplantation.

The association of colonic diverticulitis with chronic renal failure is well known. In those patients with "adult" autosomal dominant polycystic kidney disease, colonic diverticulitis is an especially common complication. We present two young patients (one teenager and one mid-twenties) who developed intra-abdominal abscess several years after renal transplantation. Neither patient had autosomal dominant polycystic disease nor a known history of gastrointestinal problems but both proved to have underlying, previously unsuspected colonic diverticular disease with abscess formation.

Abscess↗
PubMed1987

Reactogenicity and immunogenicity of the newly developed purified chick embryo cell (PCEC)-rabies vaccine in man.

Purified Chick Embryo Cell (PCEC) rabies vaccine was given to 88 healthy adults according to six different vaccination schedules. Local side effects were reported on reactivity forms after 16.4% of PCECV injections, general symptoms were recorded after 15.1% of the 292 doses administered. IgE antibodies specific for chicken proteins determined by the Radio Allergo Sorbens Test (RAST) could not be shown before and after the vaccinations. With no exception, all 88 vaccinees developed high titres of complement-fixing and neutralizing antibodies as determined by the Rapid Fluorescent Focus Inhibition Test and Serum Mouse Neutralization Test. For the first time, induction of serum interferon by PCEC rabies vaccine has been shown in man. In rabies vaccination, PCEC vaccine seems to be as effective as Human Diploid Cell Strain (HDCS) vaccine.

Adult↗