Biomedical subjects

A Berman

Publications and source records attributed to A Berman.

At least 19 recordsLinked to original sources

PubMed2006

Lung-surfactant-meconium interaction: in vitro study in bulk and at the air-solution interface.

Lung surfactants (LSs) form a monolayer at the lung's alveoli air-solution interface and play a crucial role in making normal breathing possible by reducing the surface tension. LS are affected by various agents that hamper their normal functioning. Tobacco smoke [Bringezu, F.; Pinkerton, K. E.; Zasadzinski, J. A. Langmuir 2003, 19, 2900-2907] and meconium, the first excrement of the newborn, are examples for such LS poison. In neonates, intrauterine aspiration of meconium is a known cause for morbidity and mortality. We studied in vitro the interactions between modified porcine LSs (Curosurf), used as LS replacement, and meconium, as well as between their artificial analogues, phospholipids mixture, and taurocholic acid (TA), respectively. The interactions were examined both in the bulk solution and at the air-water interface, representing the pre- and postnatal situations. It was found that the artificial analogues represent the natural system reliably and exhibit similar effects. TA, a principle component of bile, is an amphiphilic sterol compound in which the hydrophilic and hydrophobic moieties are presented at different faces of the sterol plane. Here we found that TA affects the structure of both monolayers at the interface and surfactant aggregates in solution. A likely poisoning mechanism is by stereoselective penetration of TA into the lamellar or monolayer structures, thus disrupting the contiguous structure of the intact monolayer or the bilayer vesicle structure.

Animals↗

PubMed2006

Extending the potential of evaporative cooling for heat-stress relief.

Factors were analyzed that limit the range of environmental conditions in which stress from heat may be relieved by evaporative cooling in shaded animals. Evaporative cooling reduces air temperature (Ta), but increases humidity. Equations were developed to predict Ta reduction as a function of ambient temperature and humidity and of humidity in cooled air. Predictions indicated that a reduction of Ta becomes marginal at humidities beyond 45%. A reduction of Ta lessens with rising ambient Ta. The impact of increasing humidity on respiratory heat loss (Hre) was estimated from existing data published on Holstein cattle. Respiratory heat loss is reduced by increased humidity up to 45%, but is not affected by higher humidity. Skin evaporative and sensible heat losses are determined not only by the humidity and temperature gradient, but also by air velocity close to the body surface. At higher Ta, the reduction in sensible heat loss is compensated for by an increased demand for Hre. High Hre may become a stressor when panting interferes with resting and rumination. Effects of temperature, humidity, air velocity, and body surface exposure to free air on Hre were estimated by a thermal balance model for lactating Holstein cows yielding 35 kg/d. The predictions of the simulations were supported by respiratory rate observations. The Hre was assumed to act as a stressor when exceeding 50% of the maximal capacity. When the full body surface was exposed to a 1.5 m/s air velocity, humidity (15 to 75%) had no significant predicted effect on Hre. For an air velocity of 0.3 m/s, Hre at 50% of the maximum rate was predicted at 34, 32.5, and 31.5 degrees C for relative humidities of 55, 65, and 75%, respectively. Similar results were predicted for an animal with two-thirds of its body surface exposed to 1.5 m/s air velocity. If air velocity was reduced for such animals to 0.3 m/s, the rise in Hre was expected to occur at approximately 25 degrees C and 50% relative humidity. Maximal rates of Hre were estimated at 27 to 30 degrees C when ambient humidity was 55% relative humidity and higher. High humidity may stress animals in evaporative cooling systems. Humidity stress may be prevented by a higher air velocity on the body surface of the animal, particularly in sheltered areas in which the exposed body surface is reduced, such as mangers and stalls. This may extend the use of evaporative cooling to less dry environments.

Air Movements↗

PubMed2005

Temperature dependence of the organization and molecular interactions within phospholipid/diacetylene Langmuir films.

Surface pressure-area isotherms and Brewster angle microscopy images of mixed binary films of dimyristoylphosphatidylcholine (DMPC) and the diacetylene 10,12-tricosadiynoic acid (TRCDA) were recorded at different temperatures and mole ratios to investigate the molecular interactions and cooperative properties of the films. The experiments revealed that segregation, on the one hand, and significant intermolecular interactions, on the other hand, both contribute to the thermodynamic properties of the phospholipids and the diacetylene assemblies. In particular, the data demonstrate that higher temperatures and greater percentage of DMPC promote repulsion between the liquid-condensed phospholipid monolayer and the TRCDA domains. In contrast, at high TRCDA mole ratios, film contraction occurred (lower molecular areas) due to TRCDA multilayer formation (at high temperature) or intermolecular affinities (at low temperature).

Acetylene↗

PubMed2005

Variations of surfactant monolayer surface density in induced steady wave regime.

Fluctuations of an insoluble surfactant concentration along the free liquid surface induced by steady surface waves are considered theoretically. The energy of a waved surface is assumed to consist of surface tension, curvature, and van der Waals energy components. Dependencies of the surface tension and the bending stiffness versus the surfactant concentration are assumed to be linear relative to some reference level. The van der Waals energy is taken in the form of interaction term for a thin film. Minimization of the total energy allows the expression for the deviations of concentration to be obtained. The distribution of a surfactant concentration relative to some reference level has been found to be periodic, with a period that is half of the wave period, and the amplitude of oscillations is a function of a wave number that is very similar to the Landau expansion of the free-energy near the critical point in phase transitions.

Journal Article↗

PubMed2005

Estimates of heat stress relief needs for Holstein dairy cows.

Estimates of environmental heat stress are required for heat stress relief measures in cattle. Heat stress is commonly assessed by the temperature-humidity index (THI), the sum of dry and wet bulb temperatures. The THI does not include an interaction between temperature and humidity, although evaporative heat loss increases with rising air temperature. Coat, air velocity, and radiation effects also are not accounted for in the THI. The Holstein dairy cow is the primary target of heat stress relief, followed by feedlot cattle. Heat stress may be estimated for a variety of conditions by thermal balance models. The models consist of animal-specific data (BW, metabolic heat production, tissue and coat insulation, skin water loss, coat depth, and minimal and maximal tidal volumes) and of general heat exchange equations. A thermal balance simulation model was modified to adapt it for Holstein cows by using Holstein data for the animal characteristics in the model, and was validated by comparing its outputs to experimental data. Model outputs include radiant, convective, skin evaporative, respiratory heat loss and rate of change of body temperature. Effects of milk production (35 and 45 kg/d), hair coat depth (3 and 6 mm), air temperature (20 to 45 degrees C), air velocity (0.2 to 2.0 m/s), air humidity (0.8 to 3.9 kPa), and exposed body surface (100, 75, and 50%) on thermal balance outputs were examined. Environmental conditions at which respiratory heat loss attained approximately 50% of its maximal value were defined as thresholds for intermediate heat stress. Air velocity increased and humidity significantly decreased threshold temperatures, particularly at higher coat depth. The effect of air velocity was amplified at high humidity. Increasing milk production from 35 to 45 kg/d decreased threshold temperature by 5 degrees C. In the lying cow, the lower air velocity in the proximity of body surface and the smaller exposed surface markedly decrease threshold temperature. The large variation in thresholds due to environmental and animal factors justifies the use of thermal balance-based indices for estimating heat stress. Such an approach may make possible estimates of threshold temperatures at which heat stress relief is required for widely different cattle types and environmental situations.

Animals↗

PubMed2004

Tissue and external insulation estimates and their effects on prediction of energy requirements and of heat stress.

Published data were used to develop improved equations to predict tissue insulation (TI) and external insulation (EI) and their effects on maintenance requirements of Holstein cattle. These are used to calculate lower critical temperature (LCT), energy cost of exposure to temperatures below LCT, and excess heat accumulating in the body at temperatures above LCT. The National Research Council classifies TI by age groups and body condition score; and in the EI equation air velocity effects are linear and coat insulation values are derived from beef animals in cold climates. These lead to low LCT values, which are not compatible with known effects of environment on the performance of Holsteins in warm climates. Equations were developed to present TI as a function of body weight, improving prediction of TI for animals of similar age but differing in body weight. An equation was developed to predict rate of decrease of TI at ambient temperatures above LCT. Nonlinear equations were developed that account for wind effects as boundary layer insulation effects dependent on body weight and air velocity. Published data were used to develop adjustments for hair coat effects on EI in Holstein cows. While by NRC equations, wind has negligible effects on heat loss, the recalculated effects of air velocity on heat loss were consistent with published effects of forced ventilation on the responses of the Holstein cow. The derived LCT was higher by 10 to 20 degrees C than that calculated by NRC (2001) and accounted for known Holstein performance in temperate and warm climates. These equations pointed to tentative significant effects of cold (-10 degrees C) on energy requirements (7 Mcal/d) further increased by 1 m/s wind (15 Mcal/d), even in high-producing cows. Needs for increased heat dissipation and estimating heat stress development at ambient temperatures above the LCT are predicted. These equations can be used to revise NRC equations for heat exchange.

Aging↗

PubMed2003

Systemic lupus erythematosus-associated pulmonary hypertension: good outcome following sildenafil therapy.

A 46-year-old woman with systemic lupus erythematosus (SLE) and concomitant severe pulmonary hypertension (PH) is described. Other secondary causes of PH including thromboembolism, phospholipid syndrome, valvular disease and interstitial pulmonary involvement were ruled out. Owing to her lack of clinical response to conventional therapy, sildenafil was begun at increasing doses up to 400 mg daily. Both clinical and hemodynamic improvement ensued. This appears to be the first clinical report of the use of sildenafil in SLE followed by resolution of severe PH.

Administration, Oral↗

PubMed2003

Effects of body surface area estimates on predicted energy requirements and heat stress.

The 0.09 x W(0.67) equation (where W = weight in kilograms) used to estimate body surface area (SA) in cattle energy requirements models was developed using measurements of sheep that weighed between 24 and 38 kg. The SA estimates it produced were compared with those of the equation 0.14 x W(0.57), based on Holstein cattle weighing 41 to 617 kg. The estimate of SA produced by the first equation was 23% greater for a 650-kg cow than that obtained by the second equation. The impact of SA estimates on thermal comfort range and development of cold and heat stress effects was calculated, using a thermal balance model, for a 600-kg cow producing 35 kg/d. Predicted metabolic heat production increment at -10 degrees C ambient temperature with 0.5 m/s wind velocity was 0.44 Mcal/d and 1.21 Mcal/d by the first and second equation, respectively. Predicted lower critical temperature (LCT) was -8.7 degrees C by the first equation and -0.6 degrees C by the second equation, an 8 degrees C difference. The LCT difference between SA estimates increased from 4.6 to 9.4 degrees C, with milk production rising from 10 to 45 kg/d. By the first equation, skin nonevaporative heat loss started to decrease at 15 degrees C and became close to nil at and ambient temperature of 35 degrees C, whereas by the second equation, respective values were 10 degrees C and 39 degrees C, a 5 degrees C shift in the estimated temperature at which thermal stress would start developing. The larger SA and skin water loss predicted by the first equation reduced by 50% the respiratory heat loss involved in maintenance of thermal balance at higher temperatures for a 600-kg cow. The second equation seems preferable for Holstein SA estimation since it is based on Holstein cattle data. It provides more adequate estimates of energy requirement in the cold and of heat stress relief needs for Holstein cattle.

Animals↗

PubMed2001

Favorable histologic findings and tensile strength at 14 years in knitted polyester aortofemoral and femoropopliteal grafts in the same patient.

Patent right and left limbs of an aortobifemoral knitted polyester graft and a patent left femoropopliteal graft, both implanted for 14 years, were removed 40 hr postmortem from a 63-year-old man. Healing studies were performed, using routine and immunocytochemistry staining scanning electron microscopy (SEM), and transmission electron microscopy (TEM) on multiple samples taken from sites sufficiently far from the anastomoses to avoid pannus healing. Evaluation by weight-elongation comparison with a fresh graft demonstrated that structural stability and strength were well preserved. Anastomoses were patent with no remarkable intimal hyperplasia. There was no thrombus on the flow surface of either graft. Histologic studies of these grafts revealed uniform through-wall tissue ingrowth and extensive patches of endothelial cells scattered over the flow surface, confirmed by factor VIII, SEM, and TEM. These findings document that long-term stable tensile strength and healing with flow surface endothelialization can be attained with knitted polyester grafts in the human.

Aorta↗

PubMed2000

Mammary infection with Staphylococcus aureus in cows: progress from inoculation to chronic infection and its detection.

The progress of Staphylococcus aureus infection from inoculation to the early chronic stage was examined in 12 Israeli-Holstein cows (four primiparous and eight multiparous) for up to 48 d after inoculation. Before inoculation, the primiparous cows were free from any infection and the multiparous cows were infected by coagulase-negative staphylococci. Two quarters in each cow were inoculated intracisternally following milking with 2000 cfu of a local prevailing Staph. aureus strain, VL-8407. Infection was established in 21 out of 24 quarters. The control quarters remained free from infection during the study, with no significant change in function. No statistically significant differences were found between primiparous and multiparous cows in the responses examined. Somatic cell count (SCC) increased within 24 h of inoculation and remained high for the duration of the study. In the infected quarters mean ln (SCC) increased within 24 h from 9.9 +/- 0.5 before inoculation to 13.0 +/- 0.2 after inoculation; most of the cells were neutrophils. N-acetyl-beta-glucosaminidase activity, expressed as ln (nnmol/min per l), was increased from 0.9 +/- 0.6 to 2.4 +/- 0.2 by inoculation, and was highly correlated with SCC. The Staph. aureus count fluctuated with no particular relationship with SCC. The phagocytic activity of neutrophils was significantly lower in the inoculated than in the control quarters and this difference increased with time after inoculation. CD8+ T lymphocytes were the main subpopulation of lymphocytes found in inoculated quarters. After inoculation, maximum but not minimum electrical conductivity (EC) recorded during milking increased significantly. The rises in maximum EC varied significantly among cows. The rises in SCC were associated with a persistent increase in EC in only one of the eight cows examined. No clinical signs were observed, and milk yield and composition were not affected during the study period. The results suggest that some strains of Staph. aureus may induce a relatively mild response in mammary glands of cows in mid lactation, and that the concomitant development of such chronic Staph. aureus infections in two quarters may not be detected by changes in the EC of composite milk and in the yield of the cow.

Acetylglucosaminidase↗

PubMed2000

Relation of familial schizophrenia to negative symptoms but not to the deficit syndrome.

OBJECTIVE: Although a family history of schizophrenia has been associated with negative symptoms, family history is inconsistently related to the presence of the deficit syndrome. METHOD: The authors assessed family history and the deficit syndrome in 99 patients with DSM-III-R-diagnosed schizophrenia who were assessed during clinical treatment. Of these 99 patients, 45 were assessed both while antipsychotic free and during antipsychotic treatment to index their treatment response. RESULTS: Patients with (N=39) and without (N=60) a family history of schizophrenia had similar proportions of the deficit syndrome. Yet family history and deficit syndrome categorizations identified a group with greater negative symptoms on the Positive and Negative Syndrome Scale. Those with a family history had greater emotional withdrawal, poor rapport, and lack of spontaneity. Groups with and without the deficit syndrome similarly differed in these symptoms but also in affective blunting, motor retardation, and passive or apathetic social withdrawal. The study involving antipsychotic-free and antipsychotic treatment phases showed main medication effects explaining positive, psychopathology, depression, and activation symptoms but not negative symptoms. Only patients without a family history had improved negative symptoms with antipsychotic treatment. CONCLUSIONS: Patients with a family history of schizophrenia had greater and more treatment-resistant negative symptoms than those without a family history. They were not more likely to have the deficit syndrome. The group with a family history had more pathology only in negative symptoms related to psychosocial function. The stable negative symptoms specifically related to the genetic vulnerability to inherit schizophrenia might be those associated with psychosocial functioning.

Adaptation, Psychological↗

PubMed2000

Schizophrenia subgroups differing in dichotic listening laterality also differ in neurometabolism and symptomatology.

Schizophrenia patients vary in right ear advantage (REA) on dichotic listening tests for assessing left hemispheric dominance for language processing. The authors examined if patients with low REA differed from other patients in symptoms and in resting brain metabolism. SPECT was conducted during visual fixation for 9 healthy control subjects and 16 schizophrenia patients: 8 with normal and 8 with diminished REA. REA-diminished patients had greater positive symptoms and lower mental status scores (all P<0.05) and had right middle temporal gyrus hypermetabolism. Both schizophrenia groups had decreased right frontal and increased medial temporal lobe metabolism vs. control subjects. REA-diminished patients had right temporal lobe hypermetabolism under a resting condition (eyes open, visual fixation). Results suggest reduced right ear (left hemisphere) advantage for dichotic word perception in schizophrenia is related to a predisposition to overactivate right temporal lobe regions and to positive symptoms. In contrast, the prefrontal-medial temporal imbalance present in both patient groups may typify the schizophrenia syndrome.

Adult↗

PubMed2000

Systemic lupus erythematosus: mortality and survival in Argentina. A multicenter study.

OBJECTIVE: To analyze the factors associated with mortality, survival and causes of death in patients with systemic lupus erythematosus (SLE) in Argentina. PATIENTS AND METHOD: A series of 366 patients with SLE (45 men and 321 women), mean age 29 y (range 11-70 y) and mean disease duration 6 y, was evaluated from 1990 to 1998. A total of 57 clinical, serological and therapeutic variables were studied. RESULTS: Five- and 10-year survival was 91% and 85% respectively. Forty four patients died (12%): 54% due to sepsis and 32% due to active SLE. Mortality risk factors included heart involvement CRR 3.82), hyperlipidemia (RR 2.72), renal damage (RR 2. 62), infections (RR 2.44), lung disease (RR 2.20) and myositis (RR 2. 07). High-dose prednisone (RR 3.4) or cyclophosphamide (RR 9.19) treatments increased the risk of sepsis (P=0.003) as a cause of death. However, corticosteroids, antimalarial agents and accumulated cyclophosphamide doses proved to be protective factors in overall mortality figures (RR <1). CONCLUSIONS: The main risk factors of death in SLE were heart involvement, hyperlipidemia and renal damage. Treatment with steroids, antimalarial agents and cyclophosphamide improved survival. High-dose corticosteroids and cyclophosphamide were associated with sepsis as a cause of death.

Adolescent↗

PubMed1999

SPECT study of visual fixation in schizophrenia and comparison subjects.

BACKGROUND: The consistent association of impaired eye movements and schizophrenia suggests a relationship between the neurobiology of the illness and visual pursuit systems. Visual fixation (VF), an eye "movement" task at zero velocity, is the simplest such abnormality in schizophrenia patients and their relatives. METHODS: We used a VF task for a functional imaging study. Six neuroleptic-free schizophrenia patients and eight gender and mean age matched comparison subjects had SPECT scans with 20 mCi of Tc99-HMPAO, during VF on a simple blue line intersection. MEDX data saved in ANALYZE format for SPM 95 was used to generate paired t-test statistical data for display in Talairach space, with rCBF changes given as Z-scores. RESULTS: Patients, compared to controls, had increased rCBF in both the parahippocampal gyrus (bilaterally) and in the right fusiform gyrus. They had decreased rCBF in the left frontal cortex, including medial and superior frontal gyri and anterior cingulate. Overall, compared to controls, patients had medial temporal lobe hyperperfusion along with left prefrontal hypoperfusion. CONCLUSIONS: These findings are consistent with the hypothesized imbalance between the medial temporal and frontal lobes that is postulated for schizophrenia. It was of interest that the relative rCBF differences between schizophrenia patients and controls in this small sample were observable with this cognitively non-demanding visual fixation task.

Adult↗

PubMed1999

A homologue of Sar1p localises to a novel trafficking pathway in malaria-infected erythrocytes.

We have identified a homologue of the GTP-binding protein, Sar1p, in Plasmodium falciparum. Sar1p is a small GTPase that is thought to play a crucial role in trafficking of proteins between the endoplasmic reticulum and the Golgi. The P.falciparum SAR1 gene is located on chromosome 4 and comprises two exons separated by a 508 bp intron. The deduced amino acid sequence of PfSar1p (GenBank accession number AF104306) shows 71% similarity (58% identity) to Sar1p from Saccharomyces cerevisiae. Expression of PfSar1p in erythrocytic stages of P. falciparum was confirmed by sequencing of a tryptic peptide derived from a polypeptide excised from an SDS-polyacrylamide gel. A recombinant protein corresponding to approximately 70% of the PfSar1p sequence was used to raise antibodies. The affinity-purified antiserum recognised a protein with an apparent molecular weight of 23 K in Western blots of malaria-infected erythrocytes but not in uninfected erythrocytes. PfSar1p was shown to be largely insoluble in non-ionic detergent and a low ionic strength buffer. Confocal immunofluorescence microscopy of malaria-infected erythrocytes was used to show that PfSar1p is located near the periphery of the parasite in discrete compartments, which appear to be distinct from the parasite endoplasmic reticulum. In addition, PfSar1p appears to be exported to structures outside the parasite in the erythrocyte cytoplasm. The export of PfSar1p to the erythrocyte cytosol is inhibited by treatment with brefeldin A. This provides the first evidence that the malaria parasite is capable of elaborating components of the classical vesicle-mediated trafficking machinery outside the boundaries of its own plasma membrane.

Amino Acid Sequence↗

PubMed1999

Soft tissues and osteo-articular infections in HIV-infected patients and other immunodeficient states.

Soft tissue and osteo-articular infections are rarely seen in patients with HIV infection and other immunodeficiency states. When present in HIV-infected patients, they tend to occur in the presence of low CD4(+)cell counts, intravascular indwelling catheters, extra-articular infection and trauma, and in intravenous drug users and haemophiliacs. A wide spectrum of clinical manifestations is seen, ranging from cellulitis and soft tissue abscesses to septic arthritis and pyomyositis. In general, the clinical picture and response to therapy is similar to that of patients without HIV infection. Causal micro-organisms are also similar to those in non-HIV populations, Staphylococcus aureus being the most common aetiological agent.

AIDS-Related Opportunistic Infections↗

PubMed1999

Obstetrical complications and childhood-onset schizophrenia.

OBJECTIVE: Increased obstetrical complications have been reported in individuals with adult-onset schizophrenia, with several studies finding an association between such complications and an earlier age at onset. Consequently, obstetrical records were examined for individuals with childhood-onset schizophrenia to determine if birth complications were more prevalent. METHOD: The birth records of 36 patients with childhood-onset schizophrenia and 35 sibling comparison subjects were rated for birth complications by two psychiatrists who were unaware of group membership. RESULTS: There were no significant differences between the groups in rates of obstetrical complications. Patients with such complications did not have a relatively earlier age at onset of schizophrenia. CONCLUSIONS: A very early age at onset of schizophrenia is probably not due to birth complications.

Age of Onset↗

PubMed1999

Human immunodeficiency virus infection associated arthritis: clinical characteristics.

OBJECTIVE: To define the frequency and characteristics of human immunodeficiency virus (HIV) associated arthritis. METHODS: A total of 270 patients with HIV infection were prospectively evaluated for the presence of rheumatic complaints. Diagnosis of HIV infection was performed by ELISA and confirmed by Western blot, and all HIV patients were classified according to the US Centers for Disease Control criteria. RESULTS: Twenty-one (7.8%) patients presented with HIV associated arthritis. Other arthritides including HLA-B27 related, such as Reiter's syndrome, psoriatic arthritis, and rheumatoid arthritis, were excluded. Seventeen were men and 4 women, with a mean age of 34.8 years (SD 11.1). Fourteen (66%) were homosexuals, 4 (19%) intravenous drug users, and 3 (14%) heterosexuals. Twelve (57%) were in stage IV, 5 (23%) in stage III, and 4 (9%) in stage II. Ten (47%) patients had oligoarticular involvement, 8 (38%) monoarticular, 2 (9%) asymmetric polyarthritis, and one (4%) symmetric polyarthritis. Rheumatoid factor and HLA-B27 antigen were negative in all (15) patients studied. The mean duration of arthritis was 2 weeks (1-24). No differences in duration of arthritis were found among the different risk factors (p = 0.811), HIV stages (p = 0.205), and type of articular involvement (p = 0.252). There was, however, a trend between the number of involved joints and stages of HIV infection (p = 0.13). CONCLUSION: The pattern of joint involvement of HIV associated arthritis is similar to that of other viral disorders: acute onset, short duration, no recurrences, and no erosive changes.

Adolescent↗