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Biomedical subjects

D Craig

Publications and source records attributed to D Craig.

At least 73 records · Page 4Linked to original sources
PubMed1992

Cigarette smoking and nicotine gum (0, 2 and 4 mg): effects upon four visual attention tasks.

Sixteen regular smokers, abstinent for 12 h prior to testing, were assessed on a battery of four visual attention tasks: rapid visual information processing (RVIP), letter cancellation, Stroop, and width of attention. Each subject was assessed under four conditions: placebo gum, 2 mg nicotine gum, 4 mg nicotine gum, and cigarette smoking (own brand), with the order of drug administration determined by latin square. Pre-post drug difference scores for letter cancellation response time demonstrated a significant monotonic dose-response function, with significantly faster performance following cigarette than placebo. RVIP response time and target detection were also affected by nicotine. One RVIP task parameter demonstrated a significant monotonic dose-response function, with highest performance under smoking. Other RVIP measures demonstrated curvilinear dose-response functions, with highest performance under nicotine gum, and broadly similar performance after placebo gum and cigarette smoking. Monotonic and inverted-U arousal/performance functions similar to these have been demonstrated in previous research with nicotine. In contrast to the significant changes in sustained attention, neither width of attention nor Stroop task performance (an index of distractability) was affected by nicotine. Resting heart rate and subjective 'need for a cigarette' showed the predicted monotonic dose-response functions following nicotine. There were no significant changes in any Profile of Mood State factor.

Adolescent↗
PubMed1992

Smoking cessation in women: effects of the menstrual cycle.

Ten females in the midcycle phase of the menstrual cycle, 10 females in the premenstrual phase of the menstrual cycle, and 10 males agreed to try and stop smoking for two consecutive days. The Smoking Motivation Questionnaire and Profile of Mood States Questionnaire (POMS) were completed by all subjects beforehand. On each "no smoking" day, the POMS and a Smoking Withdrawal Questionnaire were completed. Males and midcycle females achieved significantly greater smoking reduction than premenstrual females during the "no smoking" days. Premenstrual females reported becoming significantly more tired, confused, depressed, anxious, and irritable than midcycle females. Midcycle females reported only slight changes in feeling state during cigarette withdrawal. The position of the males was broadly intermediate between the two female groups.

Adaptation, Psychological↗
PubMed1991

Safety and efficacy of sonicated albumin microspheres in perfusion and vein graft patency assessments.

This study was designed to identify a concentration of sonicated albumin microspheres that is safe, useful in determining graft patency, and provides an estimate of regional myocardial perfusion. The study included 8 patients between 50 and 72 years of age who were undergoing coronary artery bypass grafting. All patients were hemodynamically stable with left ventricular ejection fractions greater than or equal to 0.35. None had congestive heart failure or myocardial infarction within 4 months prior to the study. All had normal baseline neurologic and renal functions, and none had experienced allergic reactions to blood products or contrast dyes. A standard median sternotomy was performed for exposure of the heart at surgery, and saphenous veins were harvested and used for grafting. Intraoperative epicardial echocardiography (EE), always in the left ventricle short-axis at midpapillary level, was performed before and after grafting to determine regional myocardial wall motion. Sonicated albumin microspheres were prepared and injected into a single vein graft using an 18-gauge needle; 20 x 10(6), 100 x 10(6), and 200 x 10(6) microspheres were injected into the first graft sequentially. All other vein grafts were injected once with the dose that gave optimal contrast enhancement in the initial graft studied. In each patient, a minimum of 3 and maximum of 5 injections were performed, and graft perfusion was studied using EE. Graft flow, blood pressure, and electrocardiographic (ECG) measurements were continuously monitored, with a final EE performed after weaning the patient off cardiopulmonary bypass to assess wall motion. Preliminary results showed that no patient had adverse effects during or after the study and all remained hemodynamically stable.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Histopathological and ultrastructural changes in simulated large colonic torsion and reperfusion in ponies.

This investigation examines the histological and ultrastructural lesions of the colonic mucosa during terminal experimental infarction and subsequent reperfusion. Four ponies were anaesthetised and subjected to surgical torsion of the colon. Biopsies were collected at hourly intervals for 3 h, at which point the torsions were corrected. Circulation was re-established for 2 h and the bowel was re-biopsied at hourly intervals. The ponies were killed while under anaesthesia. During the 3 h experimental infarction, the bowel became macroscopically thickened and dark purple. Histologically, the mucosa degenerated from Grade 0 to Grade 3. Ultrastructurally, there was progressive micro-vascular distension with erythrodiapedesis and damage to the interstitial cells. Spaces developed between the bases and sides of the columnar epithelial cells and sloughing followed subsequently. During the 2 h reperfusion interval, the mucosa continued to degenerate rapidly to a Grade 5, and was characterised by extensive interstitial damage, oedema, cellular swelling, necrosis and mitochondrial damage. The results showed that the experimentally infarcted colonic mucosa degenerated sequentially. Following circulatory reestablishment, continued rapid mucosal degeneration characteristic of reperfusion injury occurred. Reperfusion injury is probably responsible, at least in part, for the often poor outcome of infarcted bowel in horses following surgical correction.

Animals↗
PubMed1987

The sequence of chromosome 3 loci AHSG:TF:CHE1.

A large Hutterite kindred was examined for possible linkage between the chromosome 3 markers; cholinesterase (CHE1), transferrin (TF), and alpha-2HS glycoprotein (AHSG). Linkage between TF and AHSG was suggested in males (z = 1.515, theta = 0.08) and between CHE1 and TF(z = 0.661, theta = 0.21). However, linkage between CHE1 and AHSG in males was not established. Based on lods and a nuclear family informative for all three loci a possible chromosomal alignment for the loci is presented.

Cholinesterases↗
PubMed1984

Assessment of the survival and the clinical results of Stanmore total knee replacements.

We review 210 Stanmore knee replacements in 163 patients to assess the survival of the prostheses and the long-term results. The annual rate of failure reached a maximum of 4.6% in the fourth year after operation; thereafter it declined to reach zero by the eighth year. Between two and eight years after operation, 66.3% of the surviving knees were completely free of pain and 30.2% had mild retropatellar pain. Fixed flexion deformities present before operation were completely corrected in 73% of the knees, and varus or valgus deformities were invariably corrected. Stability was always restored to unstable knees and 80.8% of knees flexed to 90 degrees or more after replacement. Aseptic loosening (8.1%), prosthetic infection (4.3%) and femoral fracture (2.9%) led to 8.5% of the prostheses being revised or removed over eight years. Modifications in prosthetic design and operative techniques have been introduced to minimise such complications in the future.

Adult↗
PubMed1983

Stanmore total knee replacement in rheumatoid arthritis.

Stanmore Prosthesis was used to replace 115 knees in 83 patients suffering from rheumatoid arthritis. The operative technique is simple and the prosthesis is reliable in restoring stability to the most unstable knees, correcting deformity, restoring mobility and relieving pain.

Adult↗
PubMed1981

Human kidney preservation by intracellular electrolyte flush followed by cold storage for over 24 hours.

Many transplant teams are reluctant to accept kidneys preserved with intracellular electrolyte flushing followed by simple cold storage when preservation time exceeds 24 hr. This study from one center is a comparison of 63 primary cadaver kidney grafts preserved with Collins 2 solution flush followed by cold storage for 9 to 23 1/2 hr to 42 primary cadaver kidney grafts preserved by the same method for 24 to 44 1/2 hr. Kidneys cold-stored for over 24 hr had a significantly increased requirement for dialysis in the first week following transplantation (55% versus 30%). One-month serum creatinine nadirs and actuarial graft survivals were not significantly different. Cadaver donor methylprednisolone (30 to 60 mg/kg) 2 to 9 hr prior to kidney removal reduced the requirement for first-week hemodialysis in the kidneys cold-stored for over 24 hr (23% versus 69%, P under 0.05). A human kidney preserved by the same method and cold-stored for 61 hr was successfully transplanted into a 38-year-old myelodysplastic. Satisfactory human kidney preservation can occur with intracellular electrolyte flush solutions followed by cold storage for over 24 hr when the warm ischemia time is very short.

Cold Temperature↗
PubMed1981

Kinship and friendship networks and women's demand for primary care.

Women's perceptions of illness are examined and the effects of lay consultations and social networks on the use of general practitioner services are explored.A sample of 79 women aged 16-44 from a new estate in London completed six-week health diaries and were subsequently interviewed. Symptoms were recorded in the diaries one day in every three, and the ratio of medical consultations to symptom episodes was 1:18. Nearly three quarters of the symptom episodes that precipitated a medical consultation during the diary period were discussed first with someone who was non-medical. There was an average of 11 lay consultations for every medical consultation. Married women were most likely to consult with their husbands, and single and separated or divorced women with their mothers. The second most popular category of lay consultant, regardless of marital status, was female friends. Type of symptom seemed to have little effect on who was consulted.Large, active kinship networks appeared to predispose women to consult their general practitioners; large, active friendship networks seemed to have an opposite, if less decisive, effect. We speculate that discussions of symptoms with kin may be intense and protracted and lead to kin referrals to general practitioners. On the other hand, discussions with friends may be more casual and result in symptoms being redefined as unimportant and less in need of medical attention.

Adolescent↗
PubMedDate not supplied

Psychological functions served by nicotine chewing gum.

All 43 participants in a smoking cessation study complete Russell's (1974) Smoking Motivation Questionnaire (SMQ) before quitting, and an equivalent Nicotine gum Questionnaire (NGQ) during cessation. The profiles of SMQ and NGQ scores were very similar, showing that nicotine gum served a range of psychological functions similar to that provided by cigarettes: stress modulation, feelings of arousal and pleasure, hand/mouth activity, and nicotine dependency. Gum scores were, however, around 45% of cigarette values, as would be expected from its lower nicotine dose. Failed quitters (less than 2 weeks abstinence, N = 15), short-term quitters (3-12 weeks abstinence, N = 14), and successful quitters (+13 weeks abstinence: N = 14), did not differ on any SMQ subscale. However, they did differ significantly on the NGQ habit subscale. Thus the development of a regular gum-chewing habit during the first week of cessation was associated with eventual success in quitting. Sex differences were also apparent, with females reporting higher sedative, stimulant, and hand/mouth activity gum-questionnaire scores than males. These findings provide evidence for the construct and content validity of the NGQ, but further studies into its criterion validity and test-retest reliability are required.

Adult↗
PubMedDate not supplied

Contrast echocardiography: influence of ultrasonic machine settings, mixing conditions, and pressurization on pixel intensity and microsphere size of Albunex solutions in vitro.

To use Albunex as a blood-flow tracer, the stability and consistency of microspheres under mixing conditions must be known. This study examined the effects of mixing conditions and machine settings on the size and echogenicity of Albunex solutions in vitro. Acoustic power, log compression, time-gain compensation, and transducer frequency were varied as Albunex solutions were imaged after mixing with magnetic stirring and pressurized. Higher acoustic power and lower transducer frequency decreased mean pixel intensity of Albunex solution images over time. Intensity, size, and number of Albunex microspheres were not significantly different between stirring speeds. The echogenicity of the Albunex solutions decreased with pressurization, and the critical pressure necessary to reduce the intensity to half its initial value increased with the logarithm of concentration (r = 0.91; p < 0.001). The microsphere size decreased with pressurization and remained smaller after pressure release (3.66 +/- 2.13 versus 1.47 +/- 0.95 microns; p < 0.01). These data indicate that acoustic power and transducer frequency may affect the physical properties of Albunex microspheres, decreasing mean videointensity. Pressure sensitivity of Albunex caused the decrease of videointensity and microsphere size.

Albumins↗