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Biomedical subjects

L F Martin

Publications and source records attributed to L F Martin.

At least 91 records · Page 5Linked to original sources
PubMed1984

Postoperative pneumonia. Determinants of mortality.

Postoperative pneumonia continues to be a major cause of mortality on surgical services. The determinants that affect survival in patients in whom postoperative pneumonia develops are not clearly defined. We completed a retrospective analysis of 136 patients in whom postoperative pneumonia developed after they had major operative procedures between 1974 and 1980. These patients represented 1.3% of all operative cases, yet comprised 10% of the total 614 patients who died during the study period. The average age of the patients in whom pneumonia developed was 66 years. Significant determinants of death by chi 2 analysis included gram-negative pneumonitis, emergent operation, respirator-acquired pneumonia, postoperative peritonitis, and several factors that suggested that host defenses were overwhelmed (remote organ failure, positive blood cultures, or spread of infection to the second lung). We concluded that postoperative pneumonia is a disease of elderly patients and that survival depends on the ability of the surgeon to help the patient localize and resist the challenge presented by virulent gram-negative organisms.

Aged↗
PubMed1984

Rural rotations for senior surgical residents. Influence on future practice location.

No information is available on factors that influence a surgeon's decision of where to practice. We surveyed all recent graduates of a surgical training residency program from a single institution to determine factors that influence this decision. An attempt was made to determine if a rural rotation during training ultimately influenced surgeons to locate their practices in rural areas. Ninety percent of 58 graduates responded: 44% entered a rural practice and 56% an urban and/or academic practice. A rural rotation during residency had been completed by 64% of the respondents. A significantly larger number of those who entered rural practice had completed a rural rotation than those who entered urban practice. Hometown size, level of debt, and other factors thought to be influential for other subpopulations of physicians were not found to be significant in this review.

Decision Making↗
PubMed1984

Impact of a surgical postgraduate course on undergraduate surgical performance.

Postgraduate medical education generally has one of two basic goals: to improve general cognitive knowledge or to impart technical and management skills in a narrower area of medicine. Physicians invest enormous amounts of time and money in acquiring continued medical education, but there are little data on the objective benefits derived from such efforts. Because it is so difficult to make valid assessments of additions to cognitive knowledge gained by practicing surgeons, we studied the responses of a more homogeneous group, third- and fourth-year medical students, to an intensive four-day surgical course. These students were serving a surgical clerkship and were required to attend the course. Junior medical students who attended the course received higher scores on written examinations than their peers who did not participate in the course, but this did not reach statistical significance (P = .02). On objective tests, there was no difference between the scores of the fourth-year medical students. This report emphasizes the inherent difficulty in using objective criteria to measure courses.

Clinical Competence↗
PubMed1984

Life after general surgery residency: subsequent practice patterns of chief residents.

No recent reports characterize the practice patterns of graduates of current general surgical residency programs. The University of Louisville Department of Surgery surveyed recent graduates of our program who were established in practice, to determine whether the training they had received had adequately prepared them for their subsequent positions. Ninety percent of our graduates responded to a questionnaire. More than 80% of residents still regularly performed general surgical procedures even though more than 38% had completed some additional fellowship training. More than 75% of our graduates were satisfied with their income. The vast majority were satisfied with their work load and their training. Although more data are needed to determine how practice patterns develop, no current evidence suggests that current training practices are inadequate or wasteful.

Fellowships and Scholarships↗
PubMed1983

Erythrocyte sodium-potassium-stimulated adenosine triphosphatase activity is not related to obesity.

Altered erythrocyte sodium potassium (Na,K)-stimulated adenosine triphosphatase (ATPase) activity has been cited as having pathophysiologic significance in morbidly obese man. Previous studies have failed to consider obese patients after weight loss and, therefore, did not clarify the role of ATPase deficiency as a cause or effect of the obese state. To define more completely the possible alteration of cellular thermogenesis in obesity, a study was made of three groups of people: (1) normal weight controls; (2) morbidly obese; and (3) formerly morbidly obese patients who had lost over 100 pounds after gastric bypass surgery. Erythrocyte ATPase activity was determined by use of an assay that coupled ATPase activity with NADH oxidation in the presence of excess pyruvate kinase, lactic dehydrogenase, and phosphoenolpyruvate. This coupled assay produced a continuous slope so that activity could be calculated from the initial, maximal, linear portion of the decay trace. Results did not demonstrate any statistically significant differences in Na,K-ATPase activity between groups by analysis of variance. A nonsignificant correlation of 0.086 was seen between obesity index and Na,K-ATPase activity. It is concluded that (1) erythrocyte Na,K-ATPase activity is similar in both normal and obese individuals, (2) erythrocyte Na,K-ATPase does not change with weight loss, and (3) therefore, disordered erythrocyte thermogenesis does not have a role in the development or maintenance of obesity.

Adult↗
PubMed1983

Preoperative hearing and evaluations for cochlear implant patients. A preliminary report using a Minimal Auditory Capabilities battery.

Two profoundly deaf patients were evaluated using the Minimal Auditory Capabilities (MAC) battery of speech discrimination tests. One patient was a multiple-channel cochlear implant patient (MC1) using a wearable speech-processor, the other a prospective cochlear implant patient using a hearing aid (HA). Results from the MAC battery showed that MC1 received significantly more auditory information via the speech-processor than was provided by the hearing aid to HA. These results indicated that the cochlear implant could be a suitable alternative for HA. However, the results indicated that HA gained some minimal benefit from the hearing aid and these results should be taken into consideration when deciding which ear should be implanted.

Cochlear Implants↗
PubMed1983

The effects of hydrogen-ion concentration on the respiratory efficiency of human liver mitochondria.

To examine the effects of hydrogen ion concentrations on the coupled respirations of isolated human liver mitochondria, eight patients underwent incidental liver biopsies during the conduct of abdominal surgery. Mitochondria were studied by the polarographic technique at pH of 5.5, 6.0, 6.5, 7.0, 7.5, and 8.0. Results indicated severe inhibition of nicotinamide adenine dinucleotide (NAD)-linked substrates but succinate oxidations were minimally affected. Sodium succinate was then studied as a possible substrate in the resuscitation of hemorrhagic shock. Rats were subjected to bleeding to an arterial blood pressure of 50 mm Hg for 3 hours or until 25 per cent of shed blood had to be reinfused to maintain blood pressure. Resuscitation consisted of reinfusion of all shed blood plus a volume of one of four crystalloid regimens: Ringers lactate; isotonic sodium succinate; hypertonic sodium chloride (190 mEq/l): or twice-normal, hypertonic sodium chloride (308 mEq/l). Results indicated that those rats resuscitated with sodium succinate did poorer than animals receiving alternate regimens. The failure of succinate to diffuse across the plasma membrane may explain these data. Additional studies with succinate or a chemical analogue seem warranted.

Animals↗
PubMed1982

A 12-consonant confusion study on a multiple-channel cochlear implant patient.

A consonant confusion study was undertaken on a multiple-channel cochlear implant patient using a wearable speech processing device. This patient suffered from total bilateral deafness acquired postlingually. The consonants /b/, /p/, /m/, /v/, /f/, /d/, /t/, /n/, /z/, /s/, /g/, /k/ were presented in a VCV context with the vowel /a/ as in father by a male and female speaker under three conditions: lipreading alone; electrical stimulation alone using the wearable speech processor and multiple-channel cochlear implant; lipreading in conjunction with electrical stimulation. No significant difference was detected between the results for the male and female speakers. The percentage correct scores for the pooled results of both speakers were lipreading alone--30%; electrical stimulation alone--48%; lipreading with electrical stimulation--70%. Performance was significantly better for lipreading with electrical stimulation than for lipreading alone and for electrical stimulation alone than for lipreading alone. An information transmission analysis demonstrated the effective integration of visual and auditory information for lipreading with electrical stimulation. There was a significant improvement in performance for the electrical stimulation alone condition over the 2 months of the study in contrast to no such improvement for lipreading alone.

Cochlear Implants↗
PubMed1982

Bioenergy metabolism of gastric mucosa during stress.

Previous studies have identified a cellular energy deficit in gastric mucosa after ischemia. We studied the processes of energy generation (mitochondrial function) and energy utilization (microsomal adenosine triphosphatase [ATPase] activity) in an experimental model of stress. Rabbits were divided into four groups: I, fed controls (n = 7); II, 24-hour fasted controls (n = 7); III, fasted, anesthetized, and cannulated controls (n = 7); and IV, fasted, anesthetized, cannulated, and bled rabbits. Bleeding consisted of 25 ml blood/kg into a reservoir for 60 minutes; the blood was then reinfused. Animals were killed 30 minutes after reinfusion; antral, corpus, and fundus mucosae were dissected; each region of mucosa was homogenized; and mitochondrial and microsomal fractions were isolated by differential centrifugation. No animals in group I or II had gastric ulcerations. Three of seven animals in group III and all group IV animals had corpus and fundus ulcers. No antral ulcers were seen in any group. The respiratory control index (RCI) of antral mitochondria was increased in groups II, III, and IV but was unchanged in all groups of corpus and fundus mitochondria. Studies of microsomal ATPase activity indicated increased activity of potassium-stimulated ATPase in the corpus mucosa. In the corpus mucosa, total ATPase activity was increased primarily as a consequence of increased potassium-stimulated ATPase. These data indicate that increased RCI is associated with gastric mucosal integrity in the antrum. Accelerated utilization of available adenosine triphosphate by corpus membrane ATPases may further compromise energy homeostasis during stress.

Adenosine Triphosphatases↗