PubMed Health⌕ Search

Biomedical subjects

J P White

Publications and source records attributed to J P White.

At least 19 recordsLinked to original sources
PubMed2006

Osmotic upshift transiently inhibits uptake via ABC transporters in gram-negative bacteria.

ATP-binding cassette transporters from several rhizobia and Salmonella enterica serovar Typhimurium, but not secondarily coupled systems, were inhibited by high concentrations (100 to 500 mM) of various osmolytes, an effect reversed by the removal of the osmolyte. ABC systems were also inactivated in isolated pea bacteroids, probably due to the obligatory use of high-osmolarity isolation media. Measurement of nutrient cycling in isolated pea bacteroids is impeded by this effect.

ATP-Binding Cassette Transporters↗
PubMed2002

Tuberculosis in an indigenous young white south Wales population.

Concerns about tuberculosis in young people in two linked deprived non-metropolitan communities triggered an investigation into local disease incidence and control measures. A pragmatic case-finding exercise, epidemiological enquiry and DNA genotyping were carried out to establish incidence and connections between cases over a five-year period. Of the 91 cases identified, 88 were from the white indigenous population. Approximately one third of cases were aged under thirty. Eight disease clusters were identified. Epidemiological investigation found spurious links between these, and DNA genotyping was necessary to clarify links. Seven cases and several contacts had been in prisons throughout the United Kingdom. Index cases under thirty generated more contacts, more contacts needing prophylaxis and more secondary cases than older patients. The workload resulting from tuberculosis control in younger cases was considerable. Tuberculosis remains an important problem in this population.

Adolescent↗
PubMed2001

Independent origins and horizontal transfer of bacterial symbionts of aphids.

Many insect groups have obligate associations with primary endosymbionts: mutualistic bacteria that are maternally transmitted and derived from an ancient infection. Often, the same insects are hosts to 'secondary' bacterial symbionts which are maternally transmitted but relatively labile within host lineages. To explore the dynamics of secondary symbiont associations in aphids, we characterized bacteria infecting 15 species of macrosiphine aphids using DNA sequencing, diagnostic polymerase chain reaction (PCR), diagnostic restriction digests, phylogenetic analyses, and electron microscopy to examine aphids from nature and from laboratory colonies. Three types of bacteria besides Buchnera were found repeatedly; all three fall within the Enterobacteriaceae. The R-type has a 16S rDNA less than 0.1% different from that of the secondary symbiont previously reported from Acyrthosiphon pisum and is related to Serratia species. The T-type includes a symbiont previously reported from a whitefly; the U-type comprises a new cluster near the T-type. The T-type was found in every one of 40 Uroleucon ambrosiae clones collected throughout the United States. In contrast, A. pisum individuals were infected by any combination of the three symbiont types. Secondary symbionts were maternally transmitted for 11 months within laboratory-reared A. pisum clones and were present in sexually produced eggs. PCR screens for a bacteriophage, APSE-1, indicated its presence in both A. pisum and U. ambrosiae containing secondary symbionts. Electron microscopy of R-type and T-type bacteria in A. pisum and in U. ambrosiae revealed rod-shaped organisms that attain extremely high densities within a few bacteriocytes.

Animals↗
PubMed2000

The impact of managed care on nurses' workplace learning and teaching.

This paper examines the impact of managed care on the informal learning process for nurses in a major US-based health organisation. Through the analysis of focus group data we report the nurses' view of the effect recent changes have had on the nurse/patient/care relationship. Managed care, our research indicates, has transformed the learning milieus for nurses with two effects. First, nurses have seen their need for informal learning increase while the time and context for that learning has diminished. Second, the process of teaching patients and families has also been adversely affected even as managed care creates the need for more patient education. We report the analysis of the data collected at group interviews involving nurses working in both hospital and community settings of a leading US-based HMO. All interviews took place during September of 1997 at various sites in California. This study is part of a larger Social Science Research Council of Canada funded investigation into managed care in the US and Canada.

Attitude of Health Personnel↗
PubMed2000

Postmenopausal hormone replacement: historical perspectives and current concerns.

Despite continuing evidence of its value, hormone replacement (HR) therapy is used by only a minority of postmenopausal women. Some of this reluctance may stem from concerns about the medicalization of menopause and the labeling of menopause as a state of failure or disease that needs to be treated. These concerns are understandable given the impact of previous efforts to apply erroneous biological models to women's physiology, often to their detriment. Some may assert that current attempts to describe menopause as a state of estrogen deficiency are as wrong as previous explanations that the backing up of menstrual blood required purging and bleeding. However, there is an abundance of research attesting to the value of HR in decreasing such menopausal symptoms as hot flashes and insomnia and in preventing chronic problems, including urogenital atrophy and osteoporosis. In addition, recent research suggests that estrogen may have positive effects on cognition. Questions about HR and breast cancer remain, and several studies have found a small increase in breast cancer among long-term estrogen users. The recent introduction of selective estrogen response modifiers may further increase the safety of HR therapy. Many women worried about breast cancer and other possible estrogenic effects of HR are seeking approaches they consider more natural to managing menopause, turning to such untested remedies as soy supplements and herbs. While awaiting rigorous trials, clinicians can help patients understand the consequences of relying on therapies that have unknown long-term safety and effectiveness.

Alzheimer Disease↗
PubMed1999

Prehistoric birds from New Ireland, Papua New Guinea: extinctions on a large Melanesian island.

At least 50 species of birds are represented in 241 bird bones from five late Pleistocene and Holocene archaeological sites on New Ireland (Bismarck Archipelago, Papua New Guinea). The bones include only two of seabirds and none of migrant shorebirds or introduced species. Of the 50 species, at least 12 (petrel, hawk, megapode, quail, four rails, cockatoo, two owls, and crow) are not part of the current avifauna and have not been recorded previously from New Ireland. Larger samples of bones undoubtedly would indicate more extirpated species and refine the chronology of extinction. Humans have lived on New Ireland for ca. 35,000 years, whereas most of the identified bones are 15,000 to 6,000 years old. It is suspected that most or all of New Ireland's avian extinction was anthropogenic, but this suspicion remains undetermined. Our data show that significant prehistoric losses of birds, which are well documented on Pacific islands more remote than New Ireland, occurred also on large, high, mostly forested islands close to New Guinea.

Animals↗
PubMed1999

Common but curable. Responding to symptoms of testicular cancer.

Testicular cancer is one of the most common cancers in men between the ages of 15 and 34. Symptoms of testicular cancer vary but can include scrotal nodules or swelling and a sensation of fullness or heaviness of the scrotum, which may be interpreted as pain. Four treatment options are available for testicular cancer: surgery to remove the cancer, radiation therapy, chemotherapy and bone marrow transplantation. No matter what a patient's treatment course, follow-up studies and office visits are imperative.

Adolescent↗
PubMed1996

Community-based internal medicine residency training--a report on our first two years.

Since August, 1993, internal Medicine Associates Foundation, Inc. of Tupelo and the Department of Medicine, University of Mississippi Medical Center, have been cooperating in a program of community-based Internal Medicine residency training, the first effort of its kind in the state. We are pleased to report the program an unqualified success, for the residents themselves, the participating private physicians, and the Department as a whole. As one of only a handful of ambulatory care private practice relationships in the country (approximately five percent of Internal Medicine departments have such at present), we feel that ours can serve as a model for other programs to emulate. We therefore present a report on our program's background, organizational structure, curriculum, and future plans.

Ambulatory Care↗
PubMed1996

The IPSOC project: integrating prevention strategies into ongoing care.

Each primary care clinical visit can be an opportunity to promote health and provide primary prevention and screening. An innovative prompting and reminder system (IPSOC), using computer technology as an enabler, has been developed to facilitate integration of disease prevention and health promotion into ongoing clinical care for an unemployed and working poor population. In addition, the prompting system is being converted to a database program designed to prompt providers and educate consumers about the value of health promotion, screening, and disease prevention.

Ambulatory Care↗
PubMed1990

A case of resistant tuberculosis.

We report a case of multiple drug-resistant pulmonary tuberculosis, in which treatment with two second line chemotherapy regimens was inadequate. Despite in-vitro sensitivity to ciprofloxacin the patient remained sputum positive with Mycobacterium tuberculosis after 11 months.

Antitubercular Agents↗
PubMed1990

Safety of late acetylcysteine treatment in paracetamol poisoning.

Twenty patients who had taken overdoses of paracetamol were treated with acetylcysteine between 12 and 24 hours after the incident. Although 19 patients had plasma paracetamol concentrations greater than those associated with a 90% risk of moderate to severe liver damage, this complication occurred in only seven (35%) individuals. No patient developed hepatic encephalopathy or acute renal failure and all recovered without sequelae. We conclude that acetylcysteine administration up to 24 hours following paracetamol overdose is not dangerous and may prevent further liver damage.

Acetaminophen↗
PubMed1988

Pleistocene dates for the human occupation of New Ireland, northern Melanesia.

Pleistocene dates from three cave sites indicate the human capacity to colonise across two oceanic straits to the east of a former Tasmania-Australia-New Guinea continent by 33 kyr BP. The sites demonstrate exploitation of costal marine and lowland tropical forest resources. They extend Pleistocene occupation into island Melanesia and demonstrate that the large islands of northern Melanesia have an antiquity of human occupation of the same order as the adjacent Greater Australian continent.

Animals↗
PubMed1987

Deoxyribonucleic acid (DNA) polymorphism of the alpha 1-antitrypsin gene in chronic lung disease.

Specific gene probes were used to study restriction fragment length polymorphisms of the human alpha 1-antitrypsin gene. A polymorphism due to loss of a recognition site for the restriction enzyme Taq I was identified in eight of 42 patients with bronchiectasis and nine of 49 patients with pulmonary emphysema, none of whom had alpha 1-antitrypsin deficiency. Among a control group without lung disease the polymorphism was significantly less frequent, being found in only five of 101 apparently healthy blood donors. The deoxyribonucleic acid (DNA) polymorphism was also present in two of 14 unrelated patients with alpha 1-antitrypsin deficiency, indicating a lack of association with any specific alpha 1-antitrypsin protein phenotype. The polymorphism identified in this study may be a new marker for genetic predisposition to chronic lung disease.

Adolescent↗
PubMed1987

Comparison of the effects of histamine H1- and H2-receptor agonists on large and small airways in normal and asthmatic subjects.

It is accepted that histamine H1-receptors are present on human bronchial smooth muscle and that they mediate bronchoconstriction. However, the role of the histamine H2-receptor in the airways of man is less certain. In ten non-asthmatic and five asthmatic subjects we have compared the effects of inhalation of a specific H1-receptor agonist, betahistine, a specific H2-receptor agonist, impromidine and the combined H1- and H2-receptor agonist, histamine, on specific airways conductance and measurements from partial expiratory flow-volume curves. Both histamine and betahistine induced reproducible dose-dependent bronchoconstriction in all subjects, as assessed by all measurements made. Impromidine had no effect on measurements of airways function in either group of subjects. These results confirm the presence of bronchoconstricting H1-receptors, and the absence of significant numbers of H2-receptors on human bronchial smooth muscle. There is no difference in the distribution of these receptors in normal and asthmatic subjects.

Adult↗