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Biomedical subjects

D Strickland

Publications and source records attributed to D Strickland.

At least 55 records · Page 3Linked to original sources
PubMed1994

Prenatal diagnosis of cerebellar hemorrhage: medicolegal implications.

Perinatal brain damage and compromised long-term neurologic outcome have been a topic of major concern and continuing debate. Until recently the occurrence of fetal brain injury was attributed to intrapartum events. However, evidence continues to accumulate that neurologic damage can occur during fetal life unrelated to intrapartum events. We report a case of massive cerebellar hemorrhage of unknown cause diagnosed by ultrasonography at 36 weeks of gestation after decreased fetal movements. Fetal heart rate pattern and Doppler flow study of cerebral arteries are correlated with neuropathologic findings, and the medicolegal aspects of this condition are discussed.

Adult↗
PubMed1994

Association of antihypertensive agents and blood lipids in a population-based survey.

Clinical trials indicate that many antihypertensive medications alter blood lipids. These lipid changes may be of sufficient magnitude to influence subsequent coronary heart disease rates. We examined this association in a large population sample (N = 15,918, ages 25-74, 12% on antihypertensive medication) surveyed cross-sectionally from 1980 to 1986. Subjects taking antihypertensive medication had a mean serum total cholesterol 4.0 mg per dl higher than those not taking these medications after we adjusted for age, sex, weight, smoking, alcohol, blood pressure, and exercise. High-density lipoprotein cholesterol was lower in the medicated group by 2.5 mg per dl. There was no evidence that the length of medication use was related to lipid levels.

Adult↗
PubMed1994

Metabolic correlates of theophylline therapy: a concentration-related phenomenon.

OBJECTIVE: To determine the relationship of serum theophylline concentration with electrolyte and glucose abnormalities across a broad range of theophylline concentrations. DESIGN: Retrospective review of a computerized laboratory database between June 1, 1984 and June 1, 1986. SETTING: A midwestern university medical center. PATIENTS: Eight hundred sixty-nine patients with serum theophylline concentrations of > 5.5 mumol/L and a random unmatched sample (control group) of 350 in- and outpatient adults and children with no history of reactive airways disease or theophylline exposure. RESULTS: Patients with measurable theophylline had a higher risk of hypokalemia, hyponatremia, hyperglycemia, hypophosphatemia, and hypomagnesemia compared with the unexposed control group. Unadjusted odds ratios (OR) were: (1) hypokalemia OR = 4.2 (95 percent CI 2.2 to 7.9); (2) hyponatremia OR = 5.4 (95 percent CI 2.0 to 12.9); (3) hypomagnesemia OR = 1.6 (95 percent CI 1.0 to 2.5); (4) hyperglycemia OR = 2.3 (95 percent CI 1.7 to 3.0); and (5) hypophosphatemia OR = 2.7 (95 percent CI 1.2 to 5.3). A linear concentration-response relationship was documented between serum theophylline concentration and all metabolic disturbances. CONCLUSIONS: Measurable theophylline was associated with increased risk for glucose and electrolyte abnormalities in a concentration-related fashion across a broad range of theophylline concentrations from 5.5 to > or = 110 mumol/L.

Case-Control Studies↗
PubMed1993

Effect of the immediate precursors of phenylalanine and tyrosine on growth and protein synthesis in phenylalanine- and tyrosine-deprived HeLa cells.

Although Phe is an essential amino acid in mammalian cells, its immediate precursor, beta-phenylpyruvic acid (BPP), when present in Phe-deficient medium at 10(-4) and 10(-3) M is converted at a sufficient rate to Phe to sustain growth at 60 and 100% of non-deficient control HeLa S-3 cells, respectively. In contrast, Tyr-deficient cells were unable to convert the immediate precursor of Tyr, OH-beta-phenylpyruvic acid (OHBPP), nor could BPP rescue Tyr-deficient cells. The results are considered in terms of the organization of intracellular pathways by which precursors are transaminated and made available for protein synthesis.

Cell Division↗
PubMed1993

Placental chorioangioma: prenatal diagnosis and clinical significance.

We report the prenatal diagnosis of placental chorioangioma in a 32-week intrauterine pregnancy associated with polyhydramnios and enlarged fetal cardiac size that resulted in intrauterine fetal death. Ultrasound appearance, pathophysiology, and clinical significance of this entity are discussed.

Adolescent↗
PubMed1992

Smoking status and dietary fats.

BACKGROUND: There have been several recent reports of differences in the diet of smokers versus that of nonsmokers. This has broad implications for assessment of disease risk associated with diet or smoking. METHODS: We examined dietary fats for several categories of smoking status in a large cross-sectional data set. The annual risk factor survey of a cardiovascular disease prevention trial in three pairs of upper Midwest communities includes 3,495 subjects ranging in age from 24 to 75. Smoking was assessed by self-report and thiocyanate, and diet by the Willett questionnaire. Dietary comparisons of smokers, recent quitters, long-term (over 1 year) quitters, and never-smokers were conducted. RESULTS: Previous findings of lower polyunsaturated fat intake in smokers were confirmed and extended by finding significantly elevated polyunsaturate intake among those who had quit smoking within the last year. The source of these differences is unclear, but the differences are large enough to constitute a significant contribution to disease risk for smokers or a protective effect for recent quitters. CONCLUSIONS: Future research examining risks associated with smoking or diet should control for the interaction of the two factors. The dietary differences in recent quitters, whether caused by a conscious decision to improve diet, a change in taste perception as a result of quitting, or simply the habits of those smokers who are able to quit, need further exploration.

Adult↗
PubMed1991

The effect of cuff size on blood pressure measurement in adults.

We measured blood pressure differences by cuff size in 181 adults aged 25 to 74 years, allocated to a random sequence that involved the measurement of blood pressure using a small cuff, a large cuff, and an appropriate cuff as determined by standardized arm circumference measurement. Systolic and diastolic blood pressure were underestimated by 3-5 mm Hg in men and 1-3 mm Hg in women when the cuff was one size larger than appropriate. Systolic and diastolic blood pressure were overestimated by 2-6 mm Hg in men and 3-4 mm Hg in women when the cuff was one size smaller than appropriate. In addition, 30-40% of subjects were "misclassified" when blood pressure cutpoints were used to define hypertension.

Adult↗
PubMed1991

The characteristics of antigen define the cellular source and kinetics of histamine-releasing factor induced by human peripheral-blood mononuclear cells.

Peripheral-blood leucocytes from Dermatophagoides pteronyssinus- and/or Lolium perenne-allergic patients produce in vitro histamine-releasing factor (HRF) in an allergen-specific and concentration-dependent relationship. Maximum production of HRF occurred in cultures containing as little as 10-100 pg/ml crude allergen extract, although a second peak occurred at higher concentrations (10-100 micrograms/ml). While HRF was detectable in 1-hour cultures, maximal production required 24 h in culture. In contrast, HRF induced by streptokinase/streptodornase (SK/SD) was generally maximal after 1 h. Allergen-induced HRF production was almost exclusively associated with monocytes and B cells. In contrast, peripheral-blood T cells were the major source of induced HRF production in cultures containing SK/SD. Histamine-releasing cytokines are apparently produced by different cell populations, the activation of which may be dependent upon the characteristics of the stimulating antigen.

Allergens↗
PubMed1991

X-rays: laying the foundation of modern radiology, 1896-1930.

The authors describe the initial impact and far-reaching consequences of the discovery of x-rays in 1895. Roentgen was quick to realise the importance of this mysterious new kind of ray he had discovered. As early as 1896 x-rays were already being used in surgery and medicine, replacing Bell's telephonic needle probe, which could only detect metallic objects by sound and was therefore limited to the location of objects such as bullets for removel. As x-ray diagnosis became more accurate, radiological techniques were gradually improved over the years and progressed from examination of the skeleton to imaging complex internal organs. The x-ray became vital in the detection of tuberculosis, for which it is still used today. Through the use of opaque substances such as barium sulfate it became possible to visualise the digestive tract and later advances in photographic techniques made visible the brain and almost all parts of the body. Meanwhile the dangers of radiation were recognized and after 1930 safety measures were introduced to protect radiologists and patients against overexposure. In the hundred years since its discovery the ever-widening scope of radiology has made it a fundamental resource in medical diagnosis and treatment.

History, 19th Century↗
PubMed1991

Immunoregulation of asthma: control of T-lymphocyte activation in the respiratory tract.

Allergic asthma results ultimately from inappropriate responses to non-pathogenic airborn antigens by the respiratory tract T-cell system. In order to understand how sensitization to inhaled antigens develops, it is necessary to precisely define the tissue microenvironments within which T-cells occur in the respiratory tract, and to analyse the factor(s) which regulate their local activation. This review focuses upon recent data on the distribution of T-cells and antigen presenting cells within the lung and airway tissues of man and experimental animals, and examines the available information on their responses to antigenic stimulation. We argue that in the steady state, respiratory tract T-cells are tightly regulated by a series of inherent and acquired immunosuppressive control mechanisms, which normally limit local T-cell activation to situations where antigenic exposure is accompanied by an inflammatory stimulus, such as the case with incoming pathogenic microorganisms.

Allergens↗
PubMed1990

The accuracy of portable cholesterol analyzers in public screening programs.

To determine the accuracy of portable cholesterol analyzers in public settings, four screening organizations were accompanied to cholesterol screenings where consenting participants completed the finger-stick procedure and provided a blood sample by venipuncture. The finger-stick values were compared later with the participants' blood cholesterol values obtained in a reference laboratory. The results indicated that only one of the organizations produced cholesterol measurements entirely within the acceptable range (+/- 14.2%), while the accuracy of the other three organizations ranged from 76.5% to 96.4%. Those finger-stick values that did not fall within the acceptable range tended to underestimate the laboratory cholesterol values. Additionally, classification of the persons screened based on the National Cholesterol Education Program risk categories indicated that the finger-stick values primarily tended to produce false-negative results. The variability of the results across organizations was caused partially by insufficient operator training. However, inadequate quality-control procedures for field settings and dilution of capillary blood by tissue fluid also may have contributed to the inaccurate finger-stick results.

Adolescent↗
PubMed1990

Development of an immunoaffinity process for factor IX purification.

An immunoaffinity process based on monoclonal antibody (MAb) to factor IX (FIX) has been developed. Initially, vitamin-K-dependent proteins from cryoprecipitate-poor plasma are isolated on DEAE-Sephadex. The eluate is applied to an immunoaffinity column that utilizes a divalent metal-ion-dependent MAb directed against FIX. After washing the column with high salt in the presence of magnesium ion, the FIX is eluted using a citrate- or EDTA-containing buffer. Coagulation assays and Western blots show no detectable amounts of any contaminating proteins. Purity of the FIX product is established using reduced and nonreduced Coomassie-stained SDS-PAGE and HPLC. The N-terminal 20 amino acids of the single peak of the HPLC were shown to be identical to those reported for FIX. The process shows no detectable leakage of monoclonal antibodies (MAb), efficient utilization of MAb, and provides yields greater than 95%. The use of solvent/detergent treatment as a potential viral inactivation methods is incorporated in the process. Studies with tritiated Triton X-100 indicate that the detergent can be washed out of the MAb column so that less than 1 ppm (total) Triton X-100 coelutes with the FIX.

Amino Acid Sequence↗
PubMed1990

Selective attrition of non-recirculating T cells during normal passage through the lung vascular bed.

Transient arrest of T lymphocytes in the lung vascular bed following infusion of cells subjected to in vitro manipulations has been recognized for many years as a troublesome 'artefact', and has generally been attributed to trauma-induced changes in lymphocyte surface membranes. However, a number of laboratories have reported that the trapping process also occurs under situations where lymphocyte surface damage is minimal or absent, suggesting that the phenomenon may represent an intrinsic component of normal lymphocyte circulation. Consistent with these suggestions, recent studies from our laboratory have demonstrated the presence of large numbers of T cells in collagenase digests of normal peripheral lung tissue, which cannot be removed by broncho-alveolar lavage or perfusion of the tissue vascular bed. In the present experiments we have characterized these lung T cells in SPF rats. The properties common to this population include hydroxyurea sensitivity, high CD8:CD4 ratio and high frequency of cells recently derived from the thymus, and saturation thymidine-labelling studies indicated that greater than 90% of the lung T cells had divided within a 14-day test period. Additionally, cloning studies under conditions of limiting dilution indicate markedly reduced capacity for proliferation, relative to T cells in blood or spleen. We interpret these data to indicate that selective trapping and subsequent down-regulation of non-recirculating T cells is a normal consequence of passage through the lung vascular bed.

Animals↗
PubMed1990

Hypertension Prevention Trial (HPT): food pattern changes resulting from intervention on sodium, potassium, and energy intake. Hypertension Prevention Trial Research Group.

The Hypertension Prevention Trial (HPT) was a multicenter randomized trial designed to assess the effects of long-term dietary changes on blood pressure in a normotensive population (diastolic blood pressure greater than or equal to 78 but less than 90 mm Hg) for a period of 3 years. The dietary treatments were reduction of sodium intake, increase of potassium intake, and decrease of energy intake. Estimates of changes in food intake were made by comparing 24-hour food records of the treatment and control participants. The participants in the treatment groups reported sodium intakes that were 30% to 40% lower than those of the controls. The restriction was achieved mainly by reducing intake of salt, meats, and grain products. Meats and grain products were still a major source of total sodium intake after treatment (41% to 47%), perhaps because of continued use of processed foods. Potassium intake was reported to be 16% to 25% higher in the treatment groups than in the controls, the increase achieved largely through increased consumption of fruits, with a lesser contribution from vegetables. Participants with higher initial body weights reported smaller increases in fruit and vegetable consumption than participants of normal weight, perhaps because of concerns about weight gain. Energy intake in the weight loss groups was 8% to 11% less than that of the controls. Men reported success in restricting calories from meats, dairy products, fats, beverages, and sugars. Women were less successful in restricting calories from most food groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗