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Biomedical subjects

D R Jones

Publications and source records attributed to D R Jones.

At least 271 records · Page 15Linked to original sources
PubMed1987

Habituation of the cardiac response to involuntary diving in diving and dabbling ducks.

1. Bradycardia in response to forced submergence was habituated in dabbling (Anas platyrhynchos, Linnaeus) and diving (Aythya americana, Eyton) ducks by repetitively submerging the animals, each day for several days, for periods of 40 and 20 s, respectively. The onset of pronounced bradycardia was delayed with each successive trial, until little or no bradycardia occurred during submergence. Diving bradycardia is driven by chemoreceptors in the dabbler and caused by stimulation of narial receptors in the diver. 2. Mean arterial blood pressure in dives was unchanged from pre-dive levels in both naive and trained dabbling ducks. PaO2, PaCO2 and pHa at the end of a dive were similar before and after habituation training. 3. Bradycardia occurred in dives by habituated dabbling ducks if the animal breathed 15% O2 before submergence. The ventilatory responses to breathing high and low levels of oxygen were unaffected by habituation training. 4. The changes in blood gases during dives by naive and habituated dabbling ducks were the same: therefore, in the absence of a demonstrated decrement in receptor chemosensitivity or efferent potency, the locus of habituation must reside in the central nervous system.

Animals↗
PubMed1987

The Macy reports: Combat fatigue in World War II fliers.

Having supported psychiatric investigation into the psychosomatic aspects of "war neurosis" since 1931, the Josiah Macy, Jr., Foundation published five volumes on combat fatigue and its prophylaxis, recognition, treatment, and administrative aspects during World War II. The five volumes were as follows: "War Neuroses in North Africa," by R. R. Grinker and J. P. Spiegel (1943); "Psychiatric Experiences of the Eighth Air Force," by D. W. Hasting, D. G. Wright, and B. G. Glueck (1944); "How Can the Flight Surgeon Better Treat Anxiety?" by D. D. Bond, and "Notes on Men and Groups Under Stress of Combat," by D. G. Wright (a single volume, 1945); "Personality Disturbances in Combat Fliers," by N. A. Levy (1945); and "Observations on Combat Flying Personnel," by D. G. Wright (1945). The author corresponded with Drs. Spiegel, Grinker, Glueck, and Levy about the circumstances leading to these monographs, and has combined their reminiscences and observations with a brief historical view of psychiatric practice in the U.S. Army Air Force during the war. This review contrasts two therapeutic philosophies concerning combat fatigue, and comments on the lack of more modern psychiatric data about combat flying.

Aerospace Medicine↗
PubMed1987

The healthy motivation to fly: no psychiatric diagnosis.

Aircrew mission effectiveness may uniquely be influenced by subtle psychological factors not ordinarily brought to the attention of psychiatrists. Pilots tend to be bright, articulate, and anxious to resume their aviation duties when grounded. However, these patients are usually well defended, and rarely psychologically attuned or introspective. Greater insight into what constitutes the normal, healthy motivation to fly will help those who make judgments regarding the return of grounded aviators to flying duty. A review of associated birth order, personality theory, industrial and business psychology, aerospace, and psychoanalytic literature is presented. Highlighted are the difficulties inherent in examining the motivation of a healthy, well-defended population. Our conclusion: an examiner's countertransferential feelings are the best available tool for measurement of healthy motivation.

Aerospace Medicine↗
PubMed1987

Recurrent +Gz-induced loss of consciousness.

G-LOC--+Gz-induced loss of consciousness--results in significant acute incapacitation, including a period of unconsciousness lasting approximately 15 s followed by an additional period of approximately 15 s of confusion and disorientation. During routine experimentation for other purposes, four individuals experienced recurrent (3-5) episodes of G-LOC over 6-15 min. While G-LOC was neither an intended nor a desired event, we acknowledged the difficulty of stopping very high onset +Gz (VHOG) runs rapidly enough on the basis of visual endpoints to avoid occasional G-LOCs, which occurred in this limited series of experiments at a greater rate than in our more typical protocols. The requirement to define physiologic responses of fliers to operationally-relavent VHOG profiles made the development of these data pertinent and necessary. The recurrent G-LOC episodes accentuated the psychologic reactions experienced by the subjects, and allowed detailed analysis. Three of the individuals underwent detailed psychiatric interrogation to define the resultant G-LOC reactions. In addition to the post-G-LOC difficulty in recognizing the unconsciousness episode due to amnesia, specific psychologic reactions such as suppression (denial) further complicate one's ability to recognize the episode. G-LOC episodes may also lead to a reduction in combat readiness and aggressive capability in aerial combat. Recovery from G-LOC occurs in phases characterized by specific psychologic factors. The major psychologic reactions following G-LOC include confusion, disorientation, suppression of G-LOC recognition, unreliability, altered judgment, embarrassment, dissociation, euphoria, anxiety, fear, antagonism, and a "give-up" attitude.(ABSTRACT TRUNCATED AT 250 WORDS)

Acceleration↗
PubMed1986

Stress and heart disease: evidence of associations between unemployment and heart disease from the OPCS Longitudinal Study.

The OPCS Longitudinal Study has been used to study both overall and cause-specific mortality patterns in 1971-1981 among men and women directly or indirectly affected by unemployment in April 1971. Groups studied included men seeking work in 1971, the wives of men seeking work in 1971 and other women in the same households as a man seeking work in 1971. The findings of this project are summarized here and attention is focused on mortality from circulatory diseases, in particular ischaemic heart disease. The study provides evidence which could be seen as supporting hypotheses about relationships between stress and overall mortality, with a marked excess for suicides. The evidence with respect to ischaemic heart disease is positive but less convincing with excess mortality from this cause principally occurring among younger unemployed men and among the wives of men who were seeking work in 1971. Given the sharp contrasts in the pattern and levels of unemployment between 1971 and 1981 it is difficult to extrapolate from these findings to the present day.

Adolescent↗
PubMed1986

Respiratory control in the treatment of panic attacks: replication and extension with concurrent measurement of behaviour and pCO2.

A case series is reported in which nine patients who experienced phobic and/or nonphobic panic attacks were given a cognitive-behavioural treatment based on the supposition that catastrophic interpretations of sensations produced by hyperventilation played an important role in their attacks. Large and rapid reductions in panic attack frequency and questionnaire report of fear were observed. Patients' resting pCO2 was significantly lower than controls and rose to normal levels during treatment.

Adult↗
PubMed1986

The contribution of nasal receptors to the cardiac response to diving in restrained and unrestrained redhead ducks (Aythya americana).

In restrained redhead ducks, forced submergence caused heart rate to fall from 100 +/- 3 beats min-1 (mean +/- S.E.M., N = 12) to a stable underwater rate of 35 +/- 4 beats min-1 (N = 12) within 5 s after submergence. Bradycardia was unaffected by breathing oxygen before a dive, but was virtually eliminated by local anaesthesia of the narial region. In contrast, in a dabbling duck (Anas platyrhynchos) bradycardia in short dives was eliminated by breathing oxygen before a dive. In unrestrained diving, on a man-made pond, heart rate in redheads diving voluntarily (y) was related to pre-dive heart rate (x) by the equation y = 76 + 0.29 +/- 0.05x +/- 17 (r2 = 0.71). Chasing, to induce submergence, had variable effects on this relationship. Local anaesthesia of the narial region inhibited voluntary diving but heart rates in chase-induced dives after nasal blockade were significantly higher, by 10-30%, than those obtained from untreated ducks in chase-induced dives. Breathing oxygen before voluntary dives had no apparent effect on heart rate after 2-5 s submergence. Voluntary head submersion by dabbling ducks caused no change in heart rate. We conclude that nasal receptors make only a minor contribution to cardiac responses in unrestrained dives, compared with forced dives, in diving ducks. Furthermore, these results show that little can be learned about cardiac responses in free diving ducks from studies of forced dives in dabblers or divers.

Anesthesia, Local↗
PubMed1986

Use of an enzyme indirect antiglobulin test for the diagnosis of autoimmune haemolytic anaemia in the dog.

Blood samples from 34 dogs with autoimmune haemolytic anaemia (AIHA) were studied using a variety of serodiagnostic tests. Enzyme enhancement of red cells was found to be necessary for an unequivocal laboratory diagnosis of AIHA because other techniques, the direct and the indirect Coombs' tests, often gave negative results. The most frequently encountered auto-antibody was an IgG, with a titre of 1024 or more.

Anemia, Hemolytic, Autoimmune↗
PubMed1986

Flying and danger, joy and fear.

U.S. Air Force fliers are all volunteers who undergo rigorous training for their profession. Their motivation may be deeprooted and emotional, or may arise from a conscious decision made in early adulthood. Some motivation is flawed and fails early. Other motivation may be eroded by a single dangerous event, by an accumulation of "close calls" (one's own or others'), or by a growing interest in nonaviation elements. Since Air Force fliers may "quit" only at some personal cost to pride or pocketbook, they may develop a fear of flying. This may be truly phobic, a situational reaction, or an awareness of personal vulnerability. Some displace anxiety about flying into somatic symptoms. The author discusses motivation to fly, its various modes of failure, and some clinical aspects of fear of flying.

Accidents, Aviation↗
PubMed1985

Hip implant infection. Treatment with resection arthroplasty and late total hip arthroplasty.

In 131 patients with an infected hip implant, treatment was surgical excision of the implant (resection arthroplasty) and delayed reconstruction with a total hip arthroplasty. Most of the patients had low-grade infections: only 5 percent had a temperature of 37.8 degrees C or higher and only 20 percent had wound drainage. Hip pain was the primary symptom of a deep infection in 90 percent. Staphylococci were the most frequently isolated causal organisms, recovered from deep tissue specimens in 84 patients. The hip was reconstructed six days to 32 years (mode, 429 days) after resection arthroplasty. At follow-up two to nine years after reconstruction, 88 percent of the 131 patients were free of infection. Recurrent sepsis was more common (p less than 0.05) in patients with incomplete acrylic cement removal or patients in whom reconstruction was performed less than 429 days after resection arthroplasty. Risk of recurrent sepsis was increased when gram-negative bacilli in pure or mixed cultures were found, but the difference was not statistically significant.

Adult↗
PubMed1985

Is the clinical trial evidence about new drugs statistically adequate?

The statistical adequacy of all papers published in the period 1976-80 describing clinical trials of five non-steroidal anti-inflammatory and two analgesic drugs introduced into the UK market in 1978 and 1979 has been assessed using a checklist of simple criteria. Most trials were reported to be randomised and double-blind. Trial designs were less satisfactory in other important respects; the sample size of most trials was inadequate to demonstrate superiority of the new drug compared with an active control therapy. The period of treatment assessment was short in view of the likelihood of prolonged prescription of drugs in these classes. It is suggested that licensing authorities should demand higher standards of clinical trial evidence offered in support of new drugs.

Anti-Inflammatory Agents↗
PubMed1985

Dietary and pharmacological alterations in endogenous angiotensin II: effect on noradrenaline pressor responsiveness in the rat.

Rats were placed on either a low sodium intake (low sodium diet 0.025% dry weight, tap water for drinking) or a high sodium intake (normal sodium diet 0.45% dry weight, 0.9% saline for drinking) for 10 days. The pressor-response curve to angiotensin II in rats previously on a high sodium intake was shifted to the left of that found in rats previously on a low sodium intake. Suppression of endogenous angiotensin II formation with captopril (0.3 mg kg-1) or acute volume repletion (3% body wt per 30 min) resulted in a significant parallel shift of the pressor-response curve for angiotensin II to the left in the low salt group. In the high salt group captopril produced a similar but smaller parallel shift of the dose-response curve to the left. Similar manipulation of endogenous angiotensin II concentrations with high and low salt intake plus captopril treatment or acute volume repletion, produced no alterations in the pressor response for noradrenaline. The attenuated in vivo response to angiotensin II in the low salt intake group may be explained in part by the suppressed vascular sensitivity to angiotensin II in this group, as measured in the isolated perfused kidney of the rat. In kidneys from rats previously on a low sodium intake, an enhanced maximal vasoconstrictor response to noradrenaline was observed as compared to kidneys from high sodium intake rats. These results indicate that, whereas alterations in endogenous angiotensin II concentrations within physiological limits affects the response to exogenous angiotensin, there is little if any effect on the pressor response to noradrenaline.

Angiotensin II↗
PubMed1985

Social class mortality differentials: artefact, selection or life circumstances?

Data from 10 years follow up of mortality in the OPCS Longitudinal Study are used to relate deaths of men in 1976-81 to their social class as recorded by the 1971 census. Explanations of social class mortality differentials are critically reviewed in the light of these new data. The similarity between the class differentials observed for men aged 15-64 years in this study and those reported in the 1970-2 Decennial Supplement on Occupational Mortality indicate that the published gradients were not in fact grossly distorted by numerator denominator biases. Distortions to gradients observed in the early years of the longitudinal study and ascribed to selective health related mobility out of employment from the principal social classes to the permanently sick had largely worn off after five years of follow up. Sharp gradients at ages over 75 years, similar to those at younger ages, suggest that, for men aged over 50 years, selective health related mobility between social classes does not contribute to differentials in mortality.

Adolescent↗