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Biomedical subjects

S M Ling

Publications and source records attributed to S M Ling.

At least 19 recordsLinked to original sources
PubMed2006

Effects of knee injection on skeletal muscle metabolism and contractile force in rats.

OBJECTIVE: We tested the hypothesis that intrusion of the knee joint capsule alters quadriceps muscle metabolism and function independently from the damage induced to knee cartilage. METHODS: Adult rats were separated into four groups: intraarticular injections of saline (SAL; n=9); intraarticular injections of papain, a model for osteoarthritis (PIA; n=7); sham injections (SHAM; n=8); and controls (CTL; n=5). 31P magnetic resonance spectroscopy (31P-MRS) was performed after 2 weeks. Spectra were obtained from the left quadriceps: two at baseline, eight during electrical stimulation with simultaneous measurement of contractile force, and 15 during recovery. 31P-MRS data were presented as the ratio of inorganic phosphate (Pi) to phosphocreatine (PCr), concentrations of PCr [PCr], intramuscular pH, and the rates and time constants of PCr breakdown during stimulation and PCr recovery. Intramuscular cytokine concentrations were measured within the quadriceps. Histologic slides of the knees were scored for severity of cartilage damage. RESULTS: The interventional groups produced values of Pi/PCr ratio, [PCr], contractile force and pH that were significantly different from CTL. These changes in muscle function were accompanied by higher concentrations of interleukin-1 observed with PIA and SAL. We did not observe any effect of cartilage damage on muscle function or metabolism. CONCLUSIONS: Knee joint intrusion alters quadriceps muscle metabolism with accelerated depletion of energy stores and fatigue during stimulation. This study demonstrates that needle intrusion into the knee joint results in muscle dysfunction, independently from the extent of cartilage damage.

Animals↗
PubMed2006

Arterial stiffness and hand osteoarthritis: a novel relationship?

OBJECTIVE: Osteoarthritis (OA) and vascular stiffening may share elements of common pathogenesis, but their potential relatedness has been the focus of little prior inquiry. We tested the hypothesis that these two aging-associated conditions are related to each other. METHOD: We analyzed cross-sectional data from 256 participants of the Baltimore Longitudinal Study of Aging (BLSA), a study of normative aging. All underwent measurement of arterial pulse wave velocity (PWV), an index of vascular stiffness, as well as hand radiographs that were graded for evidence of OA. Twenty total joints across three joint groups (distal interphalangeal [DIP], proximal interphalangeal [PIP], carpal-metacarpal [CMC]) were each assigned a Kellgren-Lawrence grade (K-L) of 0 (normal) through 4 (severe), with K-L grades >or=2 considered evidence of definite OA. Radiographic hand OA was defined as definite OA changes in at least two of the three anatomic hand sites (DIP, PIP, CMC). OA burden was represented by the total number of affected OA joints, and a cumulative K-L grade was aggregated across all hand joint groups. The relationship of PWV with these three measures of hand OA was assessed by linear regression. RESULTS: Upon univariate analysis, the presence of radiographic hand OA (beta=218.1, P<0.01), the total number of OA joints (beta=32.9, P<0.01), and the cumulative K-L grade across all joint groups (beta=12.2, P<0.01) were each associated with increased PWV. These associations, however, were no longer significant in age-adjusted models. CONCLUSION: Although significant individual relationships between PWV and several measures of hand OA were observed, these associations were largely attributable to the confounding effect of age.

Aging↗
PubMed2005

The relationship between testosterone and molecular markers of inflammation in older men.

Aging is accompanied by a pro-inflammatory state expressed by the increasing levels of inflammatory cytokines, including interleukin-6 (IL- 6), tumor necrosis factor alpha (TNF-alpha) and interleukin- 1beta (IL-1beta). At the same time, aging is associated with a decrease in serum testosterone (T) levels. There is evidence from many experimental studies that IL-6, TNF-alpha and IL-1beta inhibit T secretion by their influence on the central (hypothalamic-pituitary) and peripheral (testicular) components of the gonadal axis. On the other hand, observational and interventional studies suggest that T supplementation reduces inflammatory markers in both young and old hypogonadal men. Preliminary data from 473 older male participants of the InCHIANTI population showed a significant inverse relationship between T and soluble IL-6 receptor (sIL-6r) levels (a soluble portion of the IL-6 receptor that may enhance the biological activity of IL-6) but not with other markers of inflammation. This study, together with previous observations, suggests that a close relationship exists between the development of a pro-inflammatory state and the decline in T levels, two trends that are often observed in aging men. In the context of this paradigm, we discuss androgen deprivation therapy, a treatment used in men with metastatic prostate cancer as an ideal model to improve our understanding of the relationship between T and inflammatory markers. We advocate the notion that changes in inflammatory markers and T in aging men are causally linked. However, longitudinal and interventional studies are needed to confirm that T can be used therapeutically, based on its anti-inflammatory properties.

Aged↗
PubMed2001

[The preparation of Ag/AgCl nanoparticle and its resonance scattering spectroscopic study].

Putting the AgCl nanoparticle as crystal nucleus and in the condition of the existence of tri-sodium citrate, the Ag+, which covers the surface of AgCl nanoparticle, photochemically reduces to Ag and thus Ag/AgCl composite nanoparticle is obtained. The spectroscopic characters of Ag/AgCl nanoparticle in aqueous solution have been studied. There are two resonance scattering peaks at 310 and 590 nm, and an absorption peak at 400 nm.

Nanotechnology↗
PubMed2000

The patterns and prevalence of hand osteoarthritis in a population of disabled older women: The Women's Health and Aging Study.

OBJECTIVE: To describe the prevalence of hand osteoarthritis (OA) by joint site, joint count and severity in a representative population of older disabled women. METHODS: 1,002 moderately to severely disabled women aged > or = 65 years were selected from a representative population of community-dwelling women. Hand OA was established using a reproducible algorithm based on self-reported pain, standardized physical examinations, hand photographs, and physician questionnaire responses. OA was categorized as either symptomatic disease, intermittently symptomatic/ asymptomatic disease, possible disease, or no disease. RESULTS: Symptomatic OA, requiring the presence of hand pain on most days for at least 1 month, occurred in approximately 23% of disabled older women in each age group, and most reported pain in the moderate to severe range. The prevalence of intermittently symptomatic/ asymptomatic OA was higher with increasing age. Finally, the most commonly affected hand OA sites were the distal interphalangeal (DIP) and the first carpometacarpal (CMC1) joint groups. CONCLUSION: These findings demonstrate the very high prevalence of clinical hand OA in disabled older women and show that a large proportion of hand OA results in substantial symptoms.

Aged↗
PubMed2000

Osteoarthritis: no cure, but many options for symptom relief.

Because curative disease-modifying medications for osteoarthritis are still not available, medical management strategies focus on pain relief. Other goals are to identify functional deficits early and to start restorative, if not preventive, rehabilitation. We review recent developments and summarize the clinical features and treatments currently available.

Age Factors↗
PubMed2000

The accuracy of self-report of physician diagnosed rheumatoid arthritis in moderately to severely disabled older women. Women's Health and Aging Collaborative Research Group.

OBJECTIVE: To determine the accuracy of self-report of physician diagnosed rheumatoid arthritis (RA) in moderately to severely disabled older women. METHODS: A total of 1002 participants in the Women's Health and Aging Study were included. These women were > or =65 years old, had an average of 4 chronic illnesses, and represented the one-third most disabled women living in the community. Self-report of a physician's diagnosis of RA was compared to cases of "definite" RA that were adjudicated using an algorithm modeled on the American College of Rheumatology criteria for RA. RESULTS: The sensitivity of self-report of physician diagnosed RA was 77%, with 90.6% specificity and 99% negative predictive value, kappa = 0.46. The positive predictive value was 34% and likely reflected the low prevalence of RA in this sample (3.1%). Five of the 6 women who did not correctly report RA were under the care of a rheumatologist. CONCLUSION: The accuracy of self-report of a physician's diagnosis of RA in this sample of disabled women with multiple chronic illnesses matched that observed in the general adult population of previous studies. Accuracy was enhanced by including report of receiving care by a rheumatologist.

Aged↗
PubMed1999

Prevalence of significant knee pain among older Americans: results from the Third National Health and Nutrition Examination Survey.

OBJECTIVE: To assess the prevalence of persistent knee pain among older adults in the US. DESIGN: A nationally representative cross-sectional survey with an in-person interview and medical examination SETTING AND PARTICIPANTS: Between 1988 and 1994, 6596 adults aged 60 to 90+ years were examined as part of the National Health and Nutrition Examination Survey III. Mexican Americans and non-Hispanic blacks were over-sampled to produce reliable estimates for these groups. MAIN OUTCOME MEASUREMENTS: Participants were asked to report whether they had experienced knee pain on most days for the 6 weeks preceding their medical exam. RESULTS: Overall, 18.1% of US men and 23.5% of US women aged 60 years and older reported knee pain. Sixty- to ninety-year-old men reported knee pain less frequently than their age-matched female counterparts. There was a trend for reports of knee pain to increase steadily as these adults aged from 60 to 85 years. The highest prevalence of knee pain was reported among 85- to 90-year-old men (23.7%) and women (30.0%). Among non-Hispanic white adults older than age 60, 18.4% of men and 22.0% of women reported knee pain. Reports of knee pain among non-Hispanic black men and Mexican American men were similar to those of their non-Hispanic white counterparts. In contrast, 26.4% of Mexican American women and 32.8% of non-Hispanic black women reported knee pain. We also found that difficulty in performing physical functioning activities was associated with a higher prevalence of knee pain. CONCLUSIONS: Many US adults older than age 60 years report knee pain, and the prevalence is higher in older adults. Reports of knee pain are highest among non-Hispanic black women and the oldest Americans. Intervention strategies are needed to prevent and better manage knee pain among older US adults to stem the adverse health consequences and diminished quality of life associated with this common problem.

Aged↗
PubMed1999

Raynaud's phenomenon in older adults: diagnostic considerations and management.

Raynaud's phenomenon (RP) is characterised by sensitivity to cold temperatures associated with either biphasic or uniphasic change in colour of the digits. Since few studies are available which include older adults, the prevalence of RP in the older adult population is estimated from surveys or studies of the general population. The causes of RP in older adults may differ significantly from those in young adults and, therefore, so would the evaluation of RP. Because of comorbitis that accompany advancing age, the management of RP in older adult patients must take into consideration toxicity and adverse reactions that may develop, especially in the frail individual. Although nonpharmacological therapy is preferable, slow-release calcium antagonists provide a relatively well tolerated and effective treatment for moderate to severe RP in older adult patients. Aggressive treatment including hospitalisation is appropriate for older adult patients during periods of critical digital ischaemia associated with RP.

Age Factors↗
PubMed1998

Osteoarthritis in older adults.

OBJECTIVE: This review highlights the clinical and pathophysiologic features of osteoarthritis (OA) of the peripheral joints and discusses the current and future management options for this common but potentially disabling disease. This article also addresses the contribution of osteoarthritis to falls and functional impairment in older people. DESIGN: A critical assessment of current data regarding the pathogenesis of osteoarthritis, current and future therapies, and the potential role of OA in falls and functional impairment in older people. CONCLUSIONS: Osteoarthritis is the most prevalent articular disease in older adults. Disease markers that will detect early disease and allow early intervention with pharmacologic agents that modify, if not halt, disease progression are much needed, but they are presently unavailable. Current management should include safe and adequate pain relief using systemic and local therapies and should also include medical and rehabilitative interventions to prevent, or at least compensate for, functional deficits. Although OA can result in impaired mobility and lower extremity function, its contribution as a cause of recurrent falls or impaired self-care, relative to other comorbid conditions, remains ill-defined. Further analysis of the determinants of disability, loss of mobility and falls in older patients with OA is needed.

Aged↗
PubMed1998

Gamma knife radiosurgery for large volume brain tumors: an analysis of acute and chronic toxicity.

Gamma Knife radiosurgery is often used to treat intracranial tumors <4 cm (approximately 13.5 cm3) in mean diameter. Larger lesions are rarely treated because of the expectation that increasing target volume will increase toxicity. We retrospectively analyzed 35 patients with primary or metastatic brain tumors of more than 13.5 cm3 treated with the Gamma Knife. Only 3 (8.5%) patients developed acute clinical toxicity. Nine (25%) patients developed post-Gamma Knife radionecrosis based on imaging studies, with only 3 of these patients (9% of the study population) having clinical progression of symptoms. Necrosis was not found to be related to prescribed dose, treatment volume or number of treated isocenters. We found no undue toxicity from the treatment of large brain tumors with the Gamma Knife.

Acute Disease↗
PubMed1996

Results of the 1993 association of residents in radiation oncology survey.

In 1993, the Association of Residents in Radiation Oncology (ARRO) conducted its tenth annual survey of all residents training in radiation oncology in the United States. The characteristics of current residents are described. Factors influencing the choice of Radiation Oncology as a medical specialty, and posttraining career plans were identified. Residents raised issues on the adequacy of training, problems in work routine, and expressed concerns about board certification and recertification, and about decreased future practice opportunities.

Adult↗
PubMed1994

Radiotherapy of primary central nervous system lymphoma in patients with and without human immunodeficiency virus. Ten years of treatment experience at the University of California San Francisco.

BACKGROUND: Classic human immunodeficiency virus (HIV) negative primary central nervous system lymphoma (PCNSL) is a relatively uncommon occurrence, whereas the incidence of HIV positive PCNSL has increased dramatically during the past 5 years. Between 2% and 6% of all patients with acquired immune deficiency syndrome (AIDS) will have PCNSL develop clinically, and as many as 11% will have PCNSL found at autopsy. In the United States, some of the earliest and most extensive experience with HIV positive PCNSL has occurred in San Francisco. This article reports on PCNSL in patients with and without HIV. METHODS: Using our diagnosis-based computer retrieval system, we identified all patients treated with radiotherapy for PCNSL between January 1982 and January 1992 and reviewed their medical records. Population characteristics, risk factors and length of survival (LOS), were analyzed. Statistical methodology included the Cox proportional hazards model and Kaplan-Meier survival curves. RESULTS: Fifty-six patients were identified with PCNSL, of which 41 were HIV positive and 15 were HIV negative. There was a fourfold increase in the total number of PCNSL cases during the time period 1987-1991 as compared with the preceding 5 years; these cases primarily were in the HIV positive group. The average Karnofsky performance score (KPS) in the HIV positive group was 50, whereas in the HIV negative group, the KPS was 35. However, the median LOS in the HIV positive group was 3 months, whereas in the HIV negative group it was 20 months. Within each group, there was a statistically significant correlation between KPS and LOS. CONCLUSIONS: Patients with HIV and PCNSL have a much shorter median LOS than do patients with PCNSL but without HIV; however, the outcome for both groups is dismal. Randomized clinical trials are needed to determine which patients with HIV might benefit from more aggressive therapy and to determine the optimal choice and dosages of chemoradiation therapy for patients with PCNSL without HIV.

Adolescent↗
PubMed1989

[Effect of an essence-restoring decoction on DNA repair capacity].

In order to observe the effect on organism DNA repair capacity after administration of Essence-Restoring Decoction (ERD), the level of peripheral lymphocyte unscheduled DNA synthesis (UDS) in 20 healthy young men, 23 healthy old men and 13 old men given ERD were detected, while the frequency of sister chromosome exchange (SCE) of mice marrow cells in 80 ICR strain male mice were detected. Ultraviolet (UV) and mitomycin-C (MMC) were used as agents to induce injury of DNA. Experimental results showed that the level of UDS in the aged person was lower than that of the young person. Comparing the level of UDS of the aged before and after medication, it was shown that the level of UDS after medication was increased, approaching that of the young. Within a range of lower doses (less than 5mg/kg weight), the SCE value of mice marrow cells raised with the increase of MMC concentration, while this values was markedly lowered in the medicated mice as compared with that of the control. It is thus suggested that ERD could enhance the DNA repair capacity and this might be a part of the mechanism of "Invigorating Kidney and retarding aging" as indicated in TCM.

Aging↗
PubMed1978

Ring 10 chromosome: 46,XX,r10(p15q26).

A teenage girl with mild retardation and some clinical features suggestive of the Turner syndrome was found to have an r10(p15q26) in blood and skin cells. Quantitative evaluation of 28 red cell enzymes, including two (hexokinase and glutamic-oxalocetic transaminase) known to be on chromosome 10, gave normal values.

Adolescent↗