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Biomedical subjects

A A Jones

Publications and source records attributed to A A Jones.

At least 37 records · Page 2Linked to original sources
PubMed1993

Iliac crest bone graft. Osteotome versus saw.

The strength of saw-harvested vs. osteotome-harvested Smith-Robinson iliac crest grafts from five fresh frozen cadavers was compared. Matched pairs of grafts were harvested, one with a saw and the other with an osteotome from equivalent locations on the two iliac crests of each pelvis. Grafts were tested to failure in axial compression, and load-displacement curves were recorded for each test. Yield load and displacement, ultimate load, and stiffness were calculated, and statistical analysis was performed with the Student t test and three-way analysis of variance. Evaluation of the 66 pairs of grafts revealed that saw-harvested grafts were consistently stronger than were matched grafts harvested with an osteotome. The middle third of the iliac crest produced significantly stronger grafts, and those harvested from younger donors were significantly stronger than those obtained from older donors. Of even greater clinical relevance, saw-harvested grafts were stiffer than osteotome-harvested grafts. Based on these findings, it is recommended that iliac crest grafts harvested for spine fusion be obtained with an oscillating saw rather than with an osteotome.

Adult↗
PubMed1993

Concentration and temperature dependence of diluent dynamics studied by line shape experiments on a phosphate ester in polycarbonate.

31P Hahn spin echo line shape and proton line shape experiments are reported on bisphenol A polycarbonate (BPAPC)-tris(2-ethylehexyl)phosphate (TOP) systems to study the concentration and temperature dependence of the local dynamics. In an earlier 31P line shape study a lattice model was presented as a framework to interpret the plasticization and antiplasticization behavior of the diluent based on a fractional population given by the type of nearest neighbor contacts in the mixed polymer-diluent glass. In this study, 31P spin echo line shapes of BPAPC, with 5%, 10% and 15% TOP, which monitor the diluent dynamics, at different temperatures and echo delay times are simulated in terms of fast- and slow-moving components, and the resulting fractional populations are compared with that predicted by the lattice model. Comparisons with the lattice model calculations are also made in the simulation of the 1H line shapes on BPAPC with 5% and 10% TOP, which probes both the polymer and diluent dynamics, and on BPAPC with 5% and 10% perdeuterated trioctylphosphate (DTOP), which detects only the polymer motion. Fairly good line shape simulations and agreement between the lattice model and the fitting results at low diluent concentrations are obtained in all cases. Restricted cone motion best describes the slow-moving component in the 31P line shape fittings. For the fast component, rotational Brownian diffusion with a distribution of correlation times corresponding to a stretched exponential function is used. An activation energy Ea of 56 kJ/mol and an exponent alpha of 0.7 for the fractional exponential correlation function are obtained and used to calculate the mechanical loss peak which was compared with the experimental loss data. The plateau character of the fractional population as a function of temperature can also be interpreted and understood in terms of the lattice model.

Benzhydryl Compounds↗
PubMed1993

Relationship of "bleeding on probing" and "gingival index bleeding" as clinical parameters of gingival inflammation.

Bleeding on probing (BOP) and the gingival index have been used to clinically characterize the degree of gingival inflammation. It is, however, unclear to what extent these parameters correlate to each other and to probing pocket depth (PD). The purpose of this clinical study was to evaluate the association between BOP and GI bleeding (scores of 2 and 3), as well as the relationship of these variables to PD, in a group of patients presenting with naturally-occurring gingivitis. Based on screening examinations of 125 subjects with at least 20 teeth, no more than 4 sites with PD over 6 mm, a BOP frequency of 30% or greater, and no systemic condition that would influence the inflammatory response, were selected. 2 weeks after screening they were examined at 6 sites per tooth for plaque index, GI, PD and BOP. A standardized pressure sensitive probe (Florida Probe) with 20 g probing force was used for BOP and PD measurements. In this population, means of 40.9% (S.E. = 1.36) BOP sites and 35.3% (S.E. = 1.81) GI bleeding sites per patient were found. A total of 20,008 sites ranging in PD up to 5.9 mm were evaluated; however, the majority of sites (19,723, 98.6%) presented with < 4 mm PD. When sites were evaluated, BOP demonstrated a positive correlation with PD, whereas GI bleeding correlated with PD. For sites characterized by the absence of BOP as well as the absence of GI bleeding (scores 0 and 1), the highest % of agreement between the 2 indices (77.7%) was found in shallow sites (0.1-2 mm).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Metastatic cystosarcoma phyllodes associated with paraplegia: an uncommon complication of an uncommon tumor.

Cystosarcoma phyllodes is a rare form of breast cancer that rarely metastasizes. This case represents the first reported case of a pathological spine fracture and neurologic injury as a result of metastatic cystosarcoma phyllodes. Physicians should be aware of a recently identified histological subtype of cystosarcoma that exhibits an increased incidence of hematogenous metastasis.

Adult↗
PubMed1992

Arthroscopic surgery of the knee on the U.S. Naval Hospital Ships during Operation Desert Shield.

Between September 1990 and January 1991, while deployed to the Persian Gulf for Operation Desert Shield, 118 patients underwent arthroscopic surgery of the knee on the U.S. Naval Hospital Ships USNS Mercy and USNS Comfort. There were 113 men and 5 women, with an average age of 28 years (range, 19-59 years). The most common findings at the time of arthroscopy were meniscus tears (53%), anterior cruciate ligament tears (29%), and normal arthroscopic examinations (9%). There were three complications, two hemarthroses and one superficial portal site infection. Seventy patients (59%) were able to be returned to duty at an average of 6 days post-operatively, obviating the need to evacuate these patients out of the Middle East theater to Europe or the United States, thus avoiding additional delay, expense, and loss of the service member to his military unit.

Adult↗
PubMed1991

The treatment of lumbar disc herniation: simple fragment excision versus disc space curettage.

The purpose of this study was to determine whether there was any difference in the clinical outcome between groups of patients treated with lumbar discectomy and vertebral endplate curettage as compared with disc fragment excision without endplate curettage. Eighty-three patients requiring lumbar disc excision for herniated nucleus pulposus were evaluated retrospectively at minimum 2-year follow-up. Forty-three patients had undergone fragment excision and disc space curettage at one center, whereas 40 patients underwent fragment excision without curettage at two other centers. There was no increased rate of reherniation or reoperation in the excision-only group. Vertebral endplate curettage carries a risk of annular penetration and damage to the great vessels. This study shows that this potentially dangerous step of the operation is unwarranted. In addition, patients who underwent endplate curettage had a higher incidence of low-back pain on follow-up.

Adult↗
PubMed1990

Immediate closed reduction of cervical spine dislocations using traction.

Cervical facet dislocations may be reduced rapidly and effectively using axial traction with weights applied at over the traditional 45-pound limit. Fifty-three sequential patients with cervical facet dislocations were reviewed. Thirty-nine patients required more than 50 pounds of traction to achieve rapid reduction. Sixty-eight percent of the entire series showed significant improvement in neurologic function. There were no cases of significant loss of function. A cadaver study confirmed that the cranial tongs could support over 100 pounds of traction. Careful application of up to 100 pounds seems to be associated with a low risk of neurologic compromise or tong failure, but results in effective reduction of dislocations.

Aged↗
PubMed1989

Long-term results of lumbar spine surgery complicated by unintended incidental durotomy.

Unintended incidental durotomy is not an infrequent complication of spinal surgery (incidence, 0.3-13% reported). Although prompt repair is advocated, little has been written regarding any consequences of primarily repaired durotomies on long-term patient outcome. A retrospective review of 450 patients undergoing lumbar spine surgery revealed 17 cases (4%) of incidental durotomy, recognized intraoperatively and repaired primarily. These patients were evaluated at long-term follow-up (mean, 25.1 months); and their results were compared with controls matched for age, diagnosis, procedure, and length of follow-up. No differences of statistical significance could be identified in comparing the outcomes of the two groups. Incidental durotomy, when recognized and repaired intraoperatively, does not increase perioperative morbidity or compromise final result.

Adult↗
PubMed1988

Failed arthrodesis of the spine for severe spondylolisthesis. Salvage by interbody arthrodesis.

Four patients who had had grade-III or grade-IV symptomatic spondylolisthesis and a failed posterior or posterolateral arthrodesis were treated with transperitoneal anterior lumbosacral interbody arthrodesis and fixation with a fibular graft; the procedure was sometimes followed by posterolateral arthrodesis of the spine. The patients were examined ten to twenty-two years after the salvage operation. At follow-up, all had a solid fusion of the fifth lumbar to the first sacral vertebra. No neurological deficits had worsened and no iatrogenic neurological deficits had developed. The slip angle had improved by an average of 23.2 degrees (range, 12 to 35 degrees).

Adolescent↗
PubMed1985

Medical care and mortality: racial differences in preventable deaths.

We analyzed deaths of blacks and whites in Alameda County, California where previous studies have documented consistent racial inequalities in health services. We classified each death during 1978 as due to preventable and manageable conditions or as "non-preventable" according to lists compiled by the Working Group on Preventable and Manageable Diseases chaired by Dr. David Rutstein. The total death rate for blacks 0-65 years of age exceeded that of whites by 58 percent (p less than .01). Rates of death due to preventable and manageable conditions for persons aged 0-65 years were 77 percent higher for blacks than for whites (p less than .01). More than one-third of the excess total death rate of blacks relative to whites could be explained by the excess of potentially preventable deaths. Our findings suggest that inequalities in health services reinforce broader social inequalities and are in part responsible for disparities in health status. Improvements in the health and longevity of blacks and other oppressed groups might be achieved by improved access to existing medical, public health, and other preventive measures.

Adolescent↗
PubMed1984

Introducing a general prompting and recording system: its effect on client and staff behavior in an institutional ward.

This study describes the evaluation of a "low-key" approach to training staff in procedures designed to increase the degree of independence of mentally handicapped people. Training leaflets describing a method of giving graded prompts to residents were distributed to staff on a hospital ward. Subsequently, checklists were introduced on which staff recorded the amount of assistance they gave residents in a variety of self-help skills. Time-sampling observations provided data on residents' engagement in such skills and their degree of independence. The amount of staff prompting was not affected by the interventions. The introduction of each intervention increased the frequency with which staff allowed residents to do tasks independently, but the effect did not persist. The amount of residents' independent activity increased prior to the introduction of the leaflets, remained stable after their introduction, and increased further when checklists were introduced. These results are discussed in terms of the training materials used and the role of supervisors in staff training.

Activities of Daily Living↗
PubMed1984

Patient transfers: medical practice as social triage.

We studied 458 consecutive patient transfers from 14 private hospitals to a public hospital emergency room during a six-month period. The transferred patients were predominantly male, young, and uninsured, and included large numbers of minority group members. We established criteria to identify patients at high risk for adverse effects of transfer and reviewed the clinical records of the 103 patients meeting these criteria. We judged that transfer resulted in substandard care for 33 of these patients, either because they were at risk for life-threatening complications in transit or because urgently needed diagnosis or therapy was delayed. In the community studied, transfer is a common and potentially dangerous medical intervention which appears to reinforce racial and class inequalities of access to medical care.

Adult↗
PubMed1983

Hypernatremic dehydration in nursing home patients: an indicator of neglect.

In order to determine the antecedents of hypernatremic dehydration the authors reviewed the records of 56 patients with this condition at two public hospitals, one of which includes a large chronic care facility. Twenty-nine patients developed hypernatremic dehydration while at nursing homes. All cases came from proprietary nursing homes, although proprietaries account for only 88 per cent of nursing home beds in the community studied (P less than 0.05). There was a cluster of patients from two nursing homes. Sixteen patients admitted from home all showed evidence of inadequate care prior to admission. Eleven patients became hypernatremic while in acute care hospitals. No patient in the public chronic care facility developed hypernatremic dehydration during the period studied. The average serum sodium concentration of patients transferred from nursing homes was significantly higher than that of patients who developed hypernatremic dehydration at home or in acute care hospitals. It is concluded that hypernatremic dehydration in an institutionalized patient may be an indicator of inadequate care, which should prompt further investigation of the living conditions of the patient.

Adult↗
PubMed1983

Public money, private control: a case study of hospital financing in Oakland and Berkeley, California.

Government support of public and private hospitals in Oakland and Berkeley, California was investigated. The private hospitals received government subsidies amounting to at least 60 per cent of their total revenues. The dollar amount of the subsidies to private hospitals was four and one-half times greater than government expenditures on the public hospital. In Oakland and Berkeley, as in many cities, public medical services have been reduced while both government health expenditures and private hospital revenues have increased sharply. The private hospitals, although all nominally non-profit, exhibit revenue maximizing behavior which results in socially unjust and medically irrational resource allocation. Funds might be found for public hospitals and clinics, and resources allocated more justly and rationally, if government expenditures in the private sector were brought under greater public scrutiny and control.

California↗
PubMed1980

Quantification of coronary arterial narrowing at necropsy in acute transmural myocardial infarction. Analysis and comparison of findings in 27 patients and 22 controls.

We quantitatively analyzed the degree and extent of coronary arterial narrowing by atherosclerotic plaques in the entire length of each of the four major coronary arteries in 27 necropsy patients with transmural acute myocardial infarction (AMI) and compared the findings with those in 22 control subjects. Of the 1403 5-mm segments examined in the 27 AMI patients, 484 (34%; controls 3%) were 76-100% narrowed in cross-sectional area by atherosclerotic plaques, 528 (38%; controls 25%) were 51-75% narrowed, 319 (23%; controls 44%) were 26-50% narrowed, and only 72 segments (5%; controls 28%) were less than or equal to 25% narrowed. The amount of severe (greater than 75%) narrowing of the right, left anterior descending and left circumflex coronary arteries by atherosclerotic plaques was similar, as was the amount of severe narrowing in the distal and proximal halves of these three arteries. The number of severely narrowed 5-mm segments did not correlate significantly with the patient's age at death, the presence or absence of a history of angina pectoris or healed myocardial infarction, or with heart weight. The men, however, had a significantly greater number of severely narrowed 5-mm segments of coronary artery than the women (p less than 0.05), and the patients with associated transmural left ventricular scars had significantly more severely narrowed segments than did patients without transmural scars.

Acute Disease↗