Takayasu's arteritis: a pathogenetic role for cytotoxic T lymphocytes?

Takayasu's arteritis is an inflammatory panarteritis of unknown aetiology affecting large elastic arteries. We examined a segment of abnormal common carotid artery removed at by-pass surgery from a 23-year-old man with typical angiographic features of Takayasu's arteritis. Using monoclonal antibodies we were able to demonstrate marked infiltration of the arterial wall with OKT8 positive lymphocytes (suppressor/cytotoxic cells) but not with OKT4 positive lymphocytes (helper cells). Studies of circulating lymphocytes showed increased numbers of "activated" cells and increased in vitro cytotoxicity against cultured human umbilical cord endothelial cells, compared to normal lymphocytes. Cellular immunological mechanisms may play an important role in the pathogenesis of Takayasu's arteritis, possibly through the direct action of cytotoxic T cells on large elastic arteries.     

Paramagnetic macrocyclic complexes as contrast agents for MR imaging: proton nuclear relaxation rate enhancement in aqueous solution and in rat tissues

Paramagnetic macrocyclic chelates show promise as magnetic resonance (MR) imaging contrast agents due to stability and relaxivity comparable to those of DTPA-type chelates. For the three copper and manganese macrocyclic complexes studied in aqueous solution, T1 and T2 relaxivities ranged from 0.14 to 5.88 mM-1sec-1 at 6.25 MHz. In rats, the intravenous administration of 16 mumol/kg of Mn(cyclam) caused the liver T1 relaxation rate to double at 15 minutes after injection. T1 measurements by pulsed MR imaging and manganese analyses on excised tissue showed that both relaxation rate (1/T1) and manganese content of liver and kidney increase linearly with the dosage of Mn(cyclam). The linear relationship between 1/T1 and manganese content can be considered an "in tissue" relaxivity plot for the agent. The resulting relaxivity is 54 mM-1sec-1 in liver, compared with 3.1 mM-1sec-1 in aqueous solution. Although this work is preliminary, the implication for medical MR imaging applications is that macrocyclic contrast agents can be effective at approximately one-tenth the current typical dose used for gadolinium DTPA.     

A family exhibiting the cis-AB genotype

Studies on blood samples from a 30-year-old woman of Korean origin, her husband and children, showed the presence of the cis-AB genotype in the mother and one child. The cis-AB red cells showed abnormal reactions with both polyclonal and monoclonal anti-B reagents and an elevated level of H antigen. The serum contained weak anti-B that reacted with normal B antigen but not with that on cis-AB cells. Normal levels of A substance but reduced levels of B and H substances were present in the saliva. Conversely, the serum showed reduced A and normal B and H blood group transferase activity.     

Controlled studies of intranasal immunotherapy for ragweed pollenosis

During 1978 a double blind study compared the efficacy of preseasonal short ragweed (RW) extract intranasal immunotherapy with a histamine placebo; in 1979 more prolonged treatment with a larger dose of polymerized ragweed (PRW) was evaluated. In neither year did the placebo-treated patients show significantly more severe disease as assessed by daily symptom diaries, examination in season, comparison of overall symptom severity with previous years or changes in nasal challenge tests. Following treatment in 1979 there was a significantly greater amount of secretory IgA and IgG ragweed antibodies secreted by the nose of the PRW-treated group, but these titers did not correlate with clinical results.     

"Could it be asthma?": the impact of a mass media campaign aimed at raising awareness about asthma in Australia

Asthma is a very common chronic illness in Australia; however,unrecognized and undertreated asthma is responsible for muchpreventable morbidity in the community. In 1988, a coalitionof private and public sector agencies was formed to conducta national mass communications program aimed at increasing awarenessabout asthma. This pilot campaign comprised a mailout to allprimary care physicians and a mass media campaign, entitled"Could it be asthma?". The impact of this media-based strategywas assessed using population surveys of 1300 adults beforeand after the campaign. Following the campaign, recall of recentasthma media messages increased from 24 to 49% (P < 0.001)and the proportion who recognized possible asthma symptoms intheir household increased from 3.4 to 5.5% following the campaign.Of those with symptoms, twice as many reported that they visiteda doctor to have their symptoms assessed after the campaign.Knowledge of asthma symptoms was significantly higher followingthe campaign (P < 0.001), after adjustment for age, sex andthe presence of asthma in the respondents family. The campaignappeared to have some success in raising awareness about asthma,and has been followed by the development of a National AsthmaCampaign in Australia focusing on reducing asthma morbidityand improving its management.     

Evaluating a test protocol for predicting maximum lactate steady state

BACKGROUND: Maximum lactate steady state (MLSS) is defined as the highest steady state exercise level one can maintain while also maintaining an equilibrium between the elimination of blood lactate and the diffusion of lactate into the blood. MLSS is an excellent tool for assessing fitness level, predicting endurance performance, and designing training programs. METHODS: This investigation assesses the validity of the Lactate Minimum Test (LMT), which consists of inducing lactic acidosis through a VO2peak test, followed by an eight-minute walking recovery and an incremental exercise test, to determine if the running velocity associated with the minimum lactate value predicts the MLSS velocity. Following this LMT, two constant velocity 28-minute runs were performed, one at the predicted MLSS velocity (trial 1) and the other 0.13 m sec-1 (4-8%) above the predicted MLSS velocity (trial 2). Ten active female subjects participated (32 +/- 7 yrs (mean +/- SD); 65.7 +/- 16.4 kg; VO2peak 40.0 +/- 7.5 ml.kg-1.min-1). RESULTS: During trial 1, there was a -0.6 +/- 0.3 mmol l-1 (mean +/- SE) change in lactate. Based on a definition of lactate steady state (LSS) as less than a 0.5 mmol.l-1 increase, this value signified LSS. A similar comparison during trial 2 revealed a 1.8 +/- 0.3 mmol.l-1 increase in lactate, signifying a workload above LSS and therefore confirming trial 1 as the maximum LSS (MLSS). CONCLUSIONS: These results suggest that the test protocol accurately predicted the MLSS velocity.     

The influence of ocular pulsatility on scanning laser Doppler flowmetry.

PURPOSE: To determine the effect of the cardiac cycle on scanning laser Doppler flowmeter measurements of retinal capillary blood flow in rhesus monkeys and humans. METHODS: Multiple scanning laser Doppler flowmetry images of rhesus monkey and human retinal capillary blood flow over a range of heart rates were obtained. Average flow values were determined for the 64 scan lines that compose the two-dimensional flow map. Cutaneous blood flow was measured simultaneously with a laser Doppler flowmeter. The temporal relationships between retinal capillary blood flow, peripheral arterial pulse, and cutaneous blood flow were determined. In addition, human retinal capillary blood flow in a 10 x 10-pixel area during different phases of the cardiac cycle was compared. RESULTS: Regular oscillations in human and rhesus monkey retinal capillary blood flow are evident as alternating bright and dark horizontal bands in scanning laser Doppler flowmetry images. These fluctuations are temporally correlated with cutaneous blood flow. Linear regression of actual vs predicted heart rate based on peaks in retinal capillary flow yielded r = 0.999 in a rhesus monkey and 0.938 in a human. Retinal capillary blood flow in a 10 x 10-pixel area fluctuated as much as 50% depending on the phase of the cardiac cycle. CONCLUSIONS: The alternating bright and dark banding pattern observed in scanning laser Doppler flowmetry scans of retinal capillary blood flow is related to the cardiac pulse. The errors introduced by pulse-related fluctuations in retinal capillary blood flow are significant and must be minimized or corrected for accurate and reproducible measurements of ocular hemodynamics.     

Secular trends in hip fracture occurrence and survival: age and sex differences

The National Hospital Discharge Survey was used to analyze secular trends from 1965 to 1993 in hip fracture incidence and in-hospital survival in the White U.S. population 50 years of age and older. Age-specific fracture rates increased significantly for males in age groups 80-84 years and 85 years and older but not for younger males. For females, age-specific rates did not change significantly over the time period. Age-specific survival rates increased for both older males and females, but the increase was greatest for the older men. Why hip fracture incidence is increasing in older males but not in females and younger males is not clear. But the high lifetime prevalence of smoking in the older cohort of males may be a factor. With rising incidence rates in elderly males, prevention efforts, which have focused primarily on women because of their high fracture rates, should target both sexes.     

National health care surveys and health care management

The bulk of medical care in the United States is provided in hospitals, physicians' offices, and nursing homes. The National Center for Health Statistics conducts three health record surveys that collect information on patient and provider characteristics and the services provided in these three settings. This paper describes each of these three surveys in terms of background (scope and data set), design, collection, processing procedures, and data dissemination. In addition, specific examples of how the survey data have been or can be used for management purposes in terms of monitoring, evaluating, and planning the utilization of health care in the United States are given.