Biomedical subjects

M Eisner

Publications and source records attributed to M Eisner.

At least 19 recordsLinked to original sources

PubMed2002

The neuromelanin of human substantia nigra and its interaction with metals.

Neuromelanin (NM) is a peculiar biochemical component of several neurons in the Substantia Nigra (SN), the target area of the degenerative process in Parkinson Disease (PD). SN NM has peculiarities as to its composition and an impressive capacity of chelating metals, iron in particular, but not exclusively. Gaining insights into the structural and functional characteristics of NM should help understanding the reasons of selective vulnerability of nigral neurons in many parkinsonian conditions. From the present data a protective role of NM can be postulated until the buffering capability toward heavy metals are exhausted. The overloading of NM with iron and other metals in neurons may trigger inflammatory and degenerative processes aggravating the underlying pathological condition.

Drug Interactions↗

PubMed2002

A national study of medical care expenditures for respiratory conditions.

This study was undertaken to estimate the magnitude of medical care expenditures among persons with respiratory conditions in the USA in 1996, and the increment in expenditures attributable to these conditions. The study data were derived from the 1996 Medical Expenditure Panel Survey, a national sample of 21,571 persons. Of the 21,571, 1,027 reported one or more respiratory condition. After weighting, the individuals may represent about 12.1 million persons in the USA. All medical care expenditures of these individuals were tabulated, stratified by comorbidity status, and then compared to those among persons with nonrespiratory conditions or with no conditions. Regression techniques were then used to estimate the increment of healthcare expenditures attributable to the respiratory conditions. From a national total of $45.3 billion, medical care expenditures averaged $3,753 among persons with respiratory conditions. Hospital stays comprised the largest component (45%). The per capita increment in total expenditures attributable to respiratory conditions ranged from $1,003-2,588, from a national total ranging from $12.1-31.3 billion. The total medical care expenditure of persons with respiratory conditions was estimated to be $45.3 billion, of which $12.1-31.3 billion represents an increment in expenditures associated with the conditions themselves.

Case-Control Studies↗

PubMed2001

Attractive and defensive functions of the ultraviolet pigments of a flower (Hypericum calycinum).

The flower of Hypericum calycinum, which appears uniformly yellow to humans, bears a UV pattern, presumably visible to insects. Two categories of pigments, flavonoids and dearomatized isoprenylated phloroglucinols (DIPs), are responsible for the UV demarcations of this flower. Flavonoids had been shown previously to function as floral UV pigments, but DIPs had not been demonstrated to serve in that capacity. We found the DIPs to be present in high concentration in the anthers and ovarian wall of the flower, suggesting that the compounds also serve in defense. Indeed, feeding tests done with one of the DIPs (hypercalin A) showed the compound to be deterrent and toxic to a caterpillar (Utetheisa ornatrix). The possibility that floral UV pigments fulfill both a visual and a defensive function had not previously been contemplated. DIPs may also serve for protection of female reproductive structures in other plants, for example in hops (Humulus lupulus). The DIPs of hops are put to human use as bitter flavoring agents and preservatives in beer.

Animals↗

PubMed2001

Production of a cyanogenic secretion by a thyridid caterpillar (Calindoea trifascialis, Thyrididae, Lepidoptera).

The thyridid caterpillar, Calindoea trifascialis, when disturbed, emits a defensive secretion from two sac-like glands that open dorsolaterally on the first abdominal segment. The larva has two arm-like protuberances that project outward from the body just in front of the gland openings. These "arms", which are wetted by secretion when the larva activates its glands, appear to function specifically for administration of the fluid. A primary component of the secretion in mandelonitrile, a cyanogenic compound, but the fluid also contains other potential deterrents, including benzaldehyde, benzoic acid, (E,E)-alpha-farnesene, and 3-methylbutyl-3-methylbutanoate. Tests done in the field in Vietnam, where the species is native, showed the secretion to be protective against ants.

Acetonitriles↗

PubMed2001

The work impact of asthma and rhinitis: findings from a population-based survey.

Asthma and rhinitis are common chronic conditions that affect adults of working age. Little is known about their relative impacts on work loss and decreased productivity. Using random digit telephone dialing, we carried out a population-survey of adults in Northern California aged 18-50 years. We interviewed 125 persons with asthma (with or without concomitant rhinitis) and 175 persons with rhinitis alone. Study eligibility was based on subject report of a physician's diagnosis of asthma and/or a rhinitis-related condition. Any adult labor force participation since condition onset was lower among those with asthma (88%) than among those with rhinitis alone (97%) (P = 0.002). In contrast, among those still employed, decreased job effectiveness was more frequently reported in the rhinitis group (43 of 121; 36%) compared to those with asthma (14 of 72; 19%) (P = 0.02). Condition-attributed lost work was common in both groups, with more than 20% reporting one or more complete or partial work days lost in the 4 weeks previous to interview. Taking into account age, gender, race, and smoking status, those with asthma were more likely to have no labor force participation after diagnosis (OR = 3.0; 95% CI 1.1-7.7) and less likely to report decreased job effectiveness among those remaining employed (OR = 0.4; 95% CI 0.2-0.9). Excluding subjects from the rhinitis group most likely to have unreported asthma based on past medication use had little impact on these associations. Both asthma and rhinitis negatively affect work productivity. Those with asthma are less likely to be employed at all, while among those remaining on the job, rhinitis is a more potent cause of decreased work effectiveness. The economic impact of asthma and rhinitis and related conditions may be under-appreciated.

Absenteeism↗

PubMed2000

Defensive use of a fecal thatch by a beetle larva (Hemisphaerota cyanea).

The larva of the tortoise beetle, Hemisphaerota cyanea (Chrysomelidae, Cassidinae), constructs a thatch from long filamentous fecal strands, beneath which it is totally concealed. The thatch is not discarded at molting but is enlarged by addition of strands as the larva grows. Thatch construction begins when the larva hatches from the egg. Pupation occurs beneath the thatch. Two predators, a coccinellid beetle larva (Cycloneda sanguinea) and a pentatomid bug (Stiretrus anchorago), were shown to be thwarted by the thatch. However, one predator, a carabid beetle (Calleida viridipennis), feeds on the larva by either forcing itself beneath the thatch or chewing its way into it. The attack behavior is stereotyped, suggesting that the beetle feeds on Hemisphaerota larvae as a matter of routine.

Adaptation, Biological↗

PubMed2000

Chemical defense against predation in an insect egg.

The larva of the green lacewing (Ceraeochrysa cubana) (Neuroptera, Chrysopidae) is a natural predator of eggs of Utetheisa ornatrix (Lepidoptera, Arctiidae), a moth that sequesters pyrrolizidine alkaloids from its larval foodplant (Fabaceae, Crotalaria spp.). Utetheisa eggs are ordinarily endowed with the alkaloid. Alkaloid-free Utetheisa eggs, produced experimentally, are pierced by the larva with its sharp tubular jaws and sucked out. Alkaloid-laden eggs, in contrast, are rejected. When attacking an Utetheisa egg cluster (numbering on average 20 eggs), the larva subjects it to an inspection process. It prods and/or pierces a small number of eggs (on average two to three) and, if these contain alkaloid, it passes "negative judgement" on the remainder of the cluster and turns away. Such generalization on the part of the larva makes sense, because the eggs within clusters differ little in alkaloid content. There is, however, considerable between-cluster variation in egg alkaloid content, so clusters in nature can be expected to range widely in palatability. To check each cluster for acceptability must therefore be adaptive for the larva, just as it must be adaptive for Utetheisa to lay its eggs in large clusters and to apportion alkaloid evenly among eggs of a cluster.

Animals↗

PubMed2000

Spray mechanism of the most primitive bombardier beetle (Metrius contractus).

The bombardier beetle Metrius contractus discharges its defensive secretion as a froth that clings to its body. When attacked from the rear, it allows the froth to build up over the gland openings near the abdominal tip; when attacked from the front, it conveys the secretion forwards along special elytral tracks. M. contractus has two-chambered defensive glands typical of bombardier beetles, and its secretion, like that of other bombardiers, is quinonoid and hot. Its frothing mechanism, however, is unique for bombardiers and possibly illustrative of the ancestral glandular discharge mechanism of these beetles. M. contractus, thus, could be the least derived of extant bombardiers.

Animals↗

PubMed1999

Sexually transmitted chemical defense in a moth (Utetheisa ornatrix).

The arctiid moth Utetheisa ornatrix is protected against predation by pyrrolizidine alkaloids (PA) that it sequesters as a larva from its food plant. Earlier work had shown that males transmit PA to the female with the sperm package and that the female bestows part of this gift on the eggs, protecting these against predation as a result. We now show that the female herself derives protection from the gift. Females deficient in PA are vulnerable to predation from spiders (Lycosa ceratiola and Nephila clavipes). If mated with a PA-laden male, the females become unacceptable as prey. The effect takes hold promptly and endures; females are unacceptable to spiders virtually from the moment they uncouple from the male and remain unacceptable as they age. Chemical data showed that the female allocates the received PA quickly to all body parts. We predict that other instances will be found of female insects being rendered invulnerable by receipt of sexually transmitted chemicals.

Animal Feed↗

PubMed1999

What do general practice receptionists think and feel about their work?

BACKGROUND: Although there is some published work acknowledging that the general practice receptionist's role is both important and difficult, receptionists' own views have rarely been sought. AIM: To explore general practice receptionists' ideas and feelings about their work. METHOD: A questionnaire was distributed to all 150 receptionists in a representative sample of 26 practices in the area covered by Leeds family health services authority. Semi-structured interviews were conducted with a representative group of 20 receptionists selected from the questionnaire sample. RESULTS: All responders were women, 60% were over 40 years old, and about half had been in the post for more than five years; four-fifths worked part-time. They had chosen the job because it dovetailed with the rest of their lives. Responders derived satisfaction from helping patients, meeting people, having good relationships with colleagues, and doing varied work. Sources of stress included difficult patients, work pressure, problems finding appointments for patients, and feeling caught between doctors' and patients' demands. Responders' experiences and views of training were diverse. Practice managers were important in making them feel consulted and supported. All had a sense of teamwork with colleagues, but many did not perceive the whole practice as a team. Many felt doctors failed to appreciate the pressure and complexity of their work. CONCLUSIONS: Receptionists' work is complex, demanding and intense, involving a high level of commitment to patients, colleagues, and the practice. Recommendations include improved appointment systems, a positive role for practice managers in relation to reception staff, and individual planning of receptionists' training. Effective teamwork among receptionists should be recognized and developed. General practitioners (GPs) are recommended to develop a greater understanding of receptionists' work.

Adult↗

PubMed1998

When defense backfires: detrimental effect of a plant's protective trichomes on an insect beneficial to the plant.

The plant Mentzelia pumila (family Loasaceae) has leaves and stems densely covered with tiny hooked trichomes. The structures entrap and kill insects and therefore are most probably protective. But they are also maladaptive in that they incapacitate a coccinellid beetle (Hippodamia convergens) that preys upon an aphid enemy (Macrosiphum mentzeliae) of the plant. The adaptive benefit provided by the trichomes is evidently offset by a cost.

Adaptation, Biological↗

PubMed1998

Rendering the inedible edible: circumvention of a millipede's chemical defense by a predaceous beetle larva.

The larva of the phengodid beetle, Phengodes laticollis, feeds on the millipede, Floridobolus penneri, without risking exposure to the repellent benzoquinones ordinarily ejected by the millipede from its defensive glands when attacked. The phengodid subdues the millipede by piercing the millipede's integument with its hollow sickle-shaped mandibles and apparently injecting gastric fluid. The infusion abruptly paralyzes the millipede, which thereby is prevented from discharging its glands. As the phengodid then imbibes the liquefied systemic contents of the dead millipede, the millipede's benzoquinones remain harmlessly confined to the glands, prevented from diffusing into the millipede's body cavity by the glands' impervious cuticular lining. At the end of the meal only the millipede's skeletal armor and glandular sacs remain uneaten. Analysis of such discarded sacs showed these to contain benzoquinones in amounts commensurate with those present in replete glands of living millipedes.

Animals↗

PubMed1998

X-ray absorption fine-structure spectroscopy studies of Fe sites in natural human neuromelanin and synthetic analogues.

X-ray absorption fine-structure spectroscopy is used to study the local environment of the iron site in natural (human) neuromelanin extracted from substantia nigra tissue and in various synthetic neuromelanins. All the materials show Fe centered in a nearest neighbor sixfold (distorted) oxygen octahedron; the Fe-O distances, while slightly different in the natural and synthetic neuromelanin, are both approximately 2.0 A. Appreciable differences arise, however, in the second (and higher) coordination shells. In this case the synthetic melanin has the four planar oxygens bound to carbon rings with Fe-C distances of approximately 2.82 and 4.13 A; the human sample does not show the 2.82 A link but instead indicates a double shell at approximately 3.45 and 3.78 A.

Biophysical Phenomena↗

PubMed1998

Primary gastroduodenal prophylaxis with omeprazole for non-steroidal anti-inflammatory drug users.

AIM: To investigate the efficacy of omeprazole 20 mg o.m. as primary prophylaxis against non-steroidal anti-inflammatory drug (NSAID)-associated ulcer disease or dyspeptic symptoms. METHODS: A parallel group study compared patients randomized to receive omeprazole 20 mg o.m. or placebo as co-therapy with on-going NSAID treatment, over 6 months, in 19 specialist centres in Ireland, Hungary, France, the UK and the USA. One hundred and sixty-nine patients taking NSAIDs regularly, chronically and above defined minimum doses entered the trial. The main outcome measure was the development of gastric or duodenal ulcers detected endoscopically, the development of multiple erosions in the stomach or duodenum, or the onset of moderate or severe dyspeptic symptoms. RESULTS: The estimated probability of remaining free of these end-points for 6 months for patients taking omeprazole was 0.78 compared to 0.53 for placebo (P = 0.004). Fourteen patients receiving placebo (16.5%) developed 15 ulcers, comprising nine gastric and six duodenal ulcers, compared to three patients (3.6%) receiving omeprazole (all gastric ulcers). Logistic regression analysis showed that older patients were less likely, whilst those with rheumatoid arthritis were more likely, to remain free of NSAID-associated problems. CONCLUSIONS: Omeprazole is an effective agent for gastroduodenal prophylaxis in patients taking NSAIDs. Its main effect is to reduce the rate of development of gastric and duodenal ulcers.

Adolescent↗

PubMed1997

Defensive production of formic acid (80%) by a carabid beetle (Galerita lecontei).

The carabid beetle Galerita lecontei has a pair of abdominal defensive glands that secrete a mixture of formic acid, acetic acid, and lipophilic components (long-chain hydrocarbons and esters). Formic acid, at the concentration of 80%, is the principal constituent. The beetle ejects the secretion as a spray, which it aims accurately toward parts of the body subjected to assault. At full capacity, the glands store 4.5 mg of formic acid (3% of body mass), enough for upward of six ejections. The beetle reloads the glands at a rate of 126 microg of formic acid per day. For the approximately 500 secretory cells of the glands, this means an hourly output of 10 ng of formic acid per cell, or about 5% of cell volume. Replenishing empty glands to their full formic acid load takes the beetle an estimated 37 days. Replenishing the 0.7 mg of formic acid expended in a single discharge takes 5.5 days.

Animals↗

PubMed1997

To treat? To befriend? To prevent? Patients' and GPs' views of the doctor's role.

OBJECTIVE: To examine and compare patients' and GPs' views of the doctor's role and patients' reasons for going to the doctor. DESIGN: A cross sectional questionnaire survey. SETTING: General practices across England. SUBJECTS: 501 patients and 68 GPs. MAIN OUTCOME MEASURES: Beliefs about the doctors' role and beliefs about patients' reasons for going to the doctor in terms of illness treatment, a psychosocial approach and preventive health care. RESULTS: A majority of both patients and GPs agreed that the doctor's role was primarily to treat illness. However, whereas patients showed greater endorsement for preventive health care and a belief that the doctor's role was to keep people healthy, GPs showed greater support for an emphasis on personal problems. In terms of patients' reasons for visiting their doctor, a majority of both patients and GPs agreed that illness prevention and illness treatment were important. However, more patients believed that patients visit the doctor for illness prevention than GPs, more of whom felt that patients seek help with their personal problems. CONCLUSION: The results indicate a mismatch between patients' and GPs' beliefs, which has implications for understanding the impact of recent changes in primary care and the effects on GPs' job satisfaction.

Adult↗

PubMed1996

Millipede defense: use of detachable bristles to entangle ants.

The millipede Polyxenus fasciculatus (Diplopoda; Polyxenida) defends itself against ants by use of a pair of bristle tufts at its rear. When attacked, it wipes the tufts against the ants, thereby causing these to become encumbered by bristles that detach from the tufts. Ants contaminated with bristles desist from their assault. The bristles have grappling hooks at the tip by which they lock onto setae of the ants and barbs along their length by which they interlink. In attempting to rid themselves of bristles, ants may succeed only in further entangling themselves by causing the bristles to become enmeshed. Ants heavily contaminated may remain entangled and die. Most millipedes have chemical defenses; polyxenids, instead, have a mechanical weapon.

Animals↗

PubMed1996

Chemical basis of courtship in a beetle (Neopyrochroa flabellata): cantharidin as precopulatory "enticing" agent.

Male Neopyrochroa flabellata have a natural affinity for cantharidin (Spanish fly). They are attracted to cantharidin baits in the field and feed on the compound if it is offered to them in the laboratory. Males that ingest cantharidin secrete cantharidin from a cephalic gland. Females sample secretion from this gland during courtship and mate preferentially with males that had fed on cantharidin. Cantharidin-unfed males can be rendered acceptable to females if cantharidin is added to their cephalic gland.

Animals↗