Primordial helium entrained by the hottest mantle plumes.

Helium isotopes provide an important tool for tracing early-Earth, primordial reservoirs that have survived in the planet's interior. Volcanic hotspot lavas, like those erupted at Hawaii and Iceland, can host rare, high 3He/4He isotopic ratios (up to 50 times the present atmospheric ratio, Ra) compared to the lower 3He/4He ratios identified in mid-ocean-ridge basalts that form by melting the upper mantle (about 8Ra; ref. 5). A long-standing hypothesis maintains that the high-3He/4He domain resides in the deep mantle, beneath the upper mantle sampled by mid-ocean-ridge basalts, and that buoyantly upwelling plumes from the deep mantle transport high-3He/4He material to the shallow mantle beneath plume-fed hotspots. One problem with this hypothesis is that, while some hotspots have 3He/4He values ranging from low to high, other hotspots exhibit only low 3He/4He ratios. Here we show that, among hotspots suggested to overlie mantle plumes, those with the highest maximum 3He/4He ratios have high hotspot buoyancy fluxes and overlie regions with seismic low-velocity anomalies in the upper mantle, unlike plume-fed hotspots with only low maximum 3He/4He ratios. We interpret the relationships between 3He/4He values, hotspot buoyancy flux, and upper-mantle shear wave velocity to mean that hot plumes-which exhibit seismic low-velocity anomalies at depths of 200 kilometres-are more buoyant and entrain both high-3He/4He and low-3He/4He material. In contrast, cooler, less buoyant plumes do not entrain this high-3He/4He material. This can be explained if the high-3He/4He domain is denser than low-3He/4He mantle components hosted in plumes, and if high-3He/4He material is entrained from the deep mantle only by the hottest, most buoyant plumes. Such a dense, deep-mantle high-3He/4He domain could remain isolated from the convecting mantle, which may help to explain the preservation of early Hadean (>4.5 billion years ago) geochemical anomalies in lavas sampling this reservoir.

Helium and lead isotopes reveal the geochemical geometry of the Samoan plume.

Hotspot lavas erupted at ocean islands exhibit tremendous isotopic variability, indicating that there are numerous mantle components hosted in upwelling mantle plumes that generate volcanism at hotspots like Hawaii and Samoa. However, it is not known how the surface expression of the various geochemical components observed in hotspot volcanoes relates to their spatial distribution within the plume. Here we present a relationship between He and Pb isotopes in Samoan lavas that places severe constraints on the distribution of geochemical species within the plume. The Pb-isotopic compositions of the Samoan lavas reveal several distinct geochemical groups, each corresponding to a different geographic lineament of volcanoes. Each group has a signature associated with one of four mantle endmembers with low (3)He/(4)He: EMII (enriched mantle 2), EMI (enriched mantle 1), HIMU (high µ = (238)U/(204)Pb) and DM (depleted mantle). Critically, these four geochemical groups trend towards a common region of Pb-isotopic space with high (3)He/(4)He. This observation is consistent with several low-(3)He/(4)He components in the plume mixing with a common high-(3)He/(4)He component, but not mixing much with each other. The mixing relationships inferred from the new He and Pb isotopic data provide the clearest picture yet of the geochemical geometry of a mantle plume, and are best explained by a high-(3)He/(4)He plume matrix that hosts, and mixes with, several distinct low-(3)He/(4)He components.

Transdermal administration of piribedil reverses MPTP-induced motor deficits in the common marmoset.

The ability of transdermal administration of the dopamine D2/D3 agonist piribedil (1-[3,4-methylenedioxybenzyl)]-4-[(2-pyrimidinyl)]piperazine) to reverse hypokinesia and other motor deficits observed in MPTP-treated common marmosets was investigated. Piribedil (2.5-10.0 mg/animal), applied directly to the skin of the abdomen as a paste, produced a long-lasting and concentration-dependent reversal of motor deficits. The antiparkinsonian actions of piribedil occurred within 10 minutes of drug administration and lasted as long as 10 hours. Transdermally applied piribedil produced a pattern of locomotor activity characteristic of normal motor behavior in this species. Symptoms of nausea (marked excessive salivation, retching, and/or vomiting) were not observed after transdermal application of piribedil. Additionally, pretreatment with the peripheral dopamine antagonist domperidone enhanced the antiparkinsonian effects of piribedil. Application to the skin of monolayer or bilayer patches impregnated with piribedil also produced a marked increase in locomotor activity and reversal of motor deficits. After application of various patch fractions (whole, one-half, or one-fourth), the increase in locomotor activity and reversal of disability correlated well with the surface area of skin covered. Measurement of serum levels of piribedil after single application of bilayer patches showed a positive relationship between drug levels and antiparkinsonian activity. Repeated daily application of piribedil bilayer patches for 5 days to MPTP-treated common marmosets primed to show dyskinesia by previous exposure to L-Dopa produced antiparkinsonian activity accompanied by dyskinetic movements. Transdermal administration of dopamine agonists such as piribedil may provide a useful means of producing a long-lasting reversal of motor deficits in Parkinson's disease while avoiding acute adverse effects such as nausea.

Effects of a community mental health service on the practice and attitudes of general practitioners.

Recent years have seen closer links developing between general practitioners and mental health specialists. A study was undertaken in Manchester to determine the effects of a new community mental health service on the practice and attitudes of general practitioners. Ten doctors had access to the community based psychiatric team over a three year period while another 10 doctors continued to use hospital services. Those with access to the team were significantly more satisfied with the specialist support services, and were more likely to give high priority to community psychiatric nurses and psychiatric social workers working as part of a primary health care team than those without access to the service. Those with access were more willing than those without access to share with psychiatrists the care of patients with chronic neurotic disorders. The community mental health team was considered particularly helpful in reducing the burden posed by patients with neurotic and psychosocial problems, but this resulted in the general practitioners doing less counselling themselves. The study did not find that the new service had an effect on the general practitioners' ability to detect or manage psychiatric illness.

The first year of an urban family practice.

The first year of an urban based family practice partnership, composed of one male and one female physician, was followed to determine disease diagnosis distribution and frequency, patient residence, and types and numbers of office procedures and laboratory tests. The diagnosis distribution and frequency were compared to studies conducted in other regions of the nation. Each partner's practice was analyzed separately to assess whether there were differences in their practices dependent on the sex of the provider. During the year, the physicians had 3,059 patient visits and recorded 4,711 problems. In all, 773 office procedures were performed; the most common were related to health maintenance. The 1,554 laboratory tests performed also showed a concentration for the purpose of health screening. This practice was less active in the areas of acute trauma and obstetrics than other reported studies. Few differences in the individual practices of the male and female physicians were noted. Categorizing the problems according to the revised diagnostic clusters demonstrates the usefulness of that system. In spite of the urban nature of the practice, a high percentage of patients using the family practice office lived in the surrounding neighborhood.

Flexible fiberoptic sigmoidoscopy: its use in family medicine.

Flexible fiberoptic sigmoidoscopy (FFS) can be both learned and taught by family physicians. The patient benefits because unnecessary referral is reduced. The physician benefits by offering more comprehensive services to the patient and by demonstrating expertise in the procedure. In a collaborative study involving family physicians performing more than 1,500 FFS examinations, both the 35-cm scope and the 65-cm scope were effective instruments, but most physicians who had experience with both scopes preferred the longer one. In addition, the results of this study support a significant advantage in pathology detection for the 65-cm scope compared with the 35-cm scope.

The psychosocial review: evaluating development and implementation in a family practice residency.

This paper presents a comprehensive system for family physicians to use in integrating psychological and social dimensions into everyday practice. Called the Psychosocial Review, this set of techniques includes a structured format for gathering information, making goal-focused assessments, and developing treatment plans. A framework for training family practice residents in the system is detailed. A research project evaluating the application of this program in two resident office practices is described. Results indicated that residents acquired information-gathering skills, but remained deficient in incorporating data into assessment and treatment. Implications for training are discussed, with the conclusion that a collaborative effort between behavioral science faculty and family physician faculty, including an emphasis on direct observation and supervision, appears to be the most promising approach to training family practice residents in behavioral science.

Preemployment multiphasic screening in an urban manpower training program.

Preemployment health examinations have long occupied a central role in industrial medicine, providing company physicians with baseline health status and physical limitations for each employee. We evaluated a similar multiphasic screening examination in 662 young, minority applicants to an urban manpower training program. Resulting from this screening was a substantial number of patients with positive serology (1%), positive gonorrhea cultures (3%), excessive daily ethanol ingestion associated with liver enlargement (13%), decreased visual acuity (24%) and dental caries (23%). These findings are markedly different than those reported for preemployment screening in industry, suggesting the need for a specific health screening protocol for applicants to manpower training programs.

Correlations between quality and pigment parameters in young Beaujolais red wines.

The commercial qualities of 15 young Beaujolais red wines from the 1974 and 1975 vintages were scored by experienced tasters in the following summers. Measurements were made of a wine colour and the separate contributions to it by the coloured anthocyanins and the polymeric pigments, b total anthocyanins (coloured plus non-coloured) and c total pigments, i.e. total anthocyanins plus total polymers (coloured and non-coloured). All the tasting and analytical data were subjected to regression analysis. Statistically significant correlations were found in both years: a. Between overall quality and the contents of total pigments, total anthocyanins, coloured anthocyanins and the tasters' mean colour scores; b. Flavour and the contents of total pigments and total anthocyanins. Thus the colour of the acidified wine (total pigment) was the most simple indication of flavour and quality in these young wines of the same variety and age. In other respects there were marked differences between the vintages. In 1974 additional significant correlations were found a between overall quality and wine colour, pH and non-coloured anthocyanins, b between flavour and colour scores and coloured anthocyanins, and c between aroma and total pigments, total anthocyanins, coloured and non-coloured anthocyanins and pH. In 1975, flavour correlated with non-coloured anthocyanins and pH. The results demonstrate the desirable effects of anthocyanins on quality.

Family practice residents' prescribing patterns.

Prescription patterns of physicians in a family practice residency office were analyzed retrospectively from the following perspectives: frequency of prescribing for individual drugs and drug categories; effect of the level of postgraduate training on prescribing patterns; and effect of patient payment systems (Medicare-Medicaid, self-pay, third-party insurance) on the number of prescriptions. Antibiotics, antihistamine-decongestants, and antihypertensive medications were the most commonly prescribed medications. Psychotropic medications were used infrequently. An average of 0.70 prescriptions was issued on each office visit. Per office visit, first-year residents averaged 0.59 prescriptions, second-year residents averaged 0.69 prescriptions, third-year residents averaged 0.72 prescriptions, and the faculty averaged 0.98 prescriptions. Patients on Medicare-Medicaid averaged 0.78 prescriptions per office visit, self-pay patients averaged 0.25 prescriptions per visit, and patients with third-party insurance averaged 1.49 prescriptions per visit. The differences in the prescription rates between each payment group were significant.