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Biomedical subjects

J H Davis

Publications and source records attributed to J H Davis.

At least 163 records · Page 9Linked to original sources
PubMed1977

Deuterium magnetic resonance studies of the interaction of lipids with membrane proteins.

The deuterium magnetic resonance spectra of lipid-protein particles containing cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase, EC 1.9.3.1) isolated from beef heart mitochondria and the specifically deuterated lipid 1-(16,16,16-trideuteropalmitoyl)-2-palmitoleoyl phosphatidylcholine are presented. These reconstituted particles are of uniform lipid and protein content; however, the spectra clearly show two environments characterized by distinctly different residual quadrupolar splittings or order parameters. The less-ordered environment shows a splitting similar to but slightly less than that of the pure lipid alone at a given temperature. The more restricted environment appears to be induced by the presence of the protein. The amount of the restricted lipid is clearly temperature dependent with a 2- to 3-fold decrease in relative amount from 2 to 22 degrees. The rate of exchange of lipid between the free and restricted environments is slower than 10(3)/sec. The significance of these phenomena is discussed.

Chemical Phenomena↗
PubMed1977

Adult respiratory distress syndrome (ARDS), sepsis, and extracorporeal membrane oxygenation (ECMO).

This report presents data obtained in the care of 830 patients requiring assisted ventilation. When these patients were divided into groups by the severity of their respiratory failure as defined by the duration of ventilatory assistance (greater than 48 hours, less than 48 hours) and level of positive end expiratory pressure (PEEP) required (greater than 5 cm HoH, less than 5 cm HoH), it was found that evidence of concurrent bacterial infection was present in the majority of patients with severe respiratory failure. This finding could not be explained by infection acquired after the onset of respiratory failure. In addition, this analysis demonstrated the important association of active pulmonary infection with the occurrence of barotrauma in these patients. Case analysis of patients subjected to extracorporeal membrane oxygenation has led to the suggestion that underlying sepsis in patients failing to respond to conventional ventilatory assistance similarly limits the usefulness of membrane oxygenator support.

Adolescent↗
PubMed1976

Pulmonary function in patients with multiple trauma and associated severe head injury.

1) Sodium and water balance and pulmonary function studies were obtained in five patients with multiple injuries, including pulmonary contusion, plus severe intracranial trauma. All patients received dexamethasone, 4-6 every 6 hours during the 72-hour study period after injury. 2) Results were compared with those from 14 previously reported patients without head injury; none had received corticosteroids. 3) Study patients with head injury achieved negative water balance and almost-zero sodium balance within 72 hours of injury be excreting a high-volume, low-sodium urine. Despite elevated alveolar-arterial oxygen gradients and low-normal pulmonary compliance initially, there was progressive improvement and no patient developed post-traumatic pulmonary insufficiency. 4) The data suggest that the "negative" effects of major intracranial trauma on the kidney, heart, and lung are cancelled by dexamethasone, or that corticosteroids protect pulmonary function in the patient with multiple injuries and prevent post-traumatic pulmonary insufficiency, perhaps through their effect on the kidney leading to rapid restoration of sodium and water balance.

Adolescent↗
PubMed1975

Complications of surgery of the abdominal aorta.

Surgery of the aorta has become a routine since Astley Cooper first attempted to ligate the aorta. It is major surgery that requires careful technic, understanding of the disease process, and a full knowledge of the complications that may ensue. Most of the complications are preventable, and if the operator recognizes their possibility, most can be prevented. When complications occur, the operator must be prepared to handle them immediately since most of them are catastrophic and usually life-threatening to the patient. Surgery of the aorta should never be performed in a hospital that does not have the backup facilities to manage these complications. This requires the immediate availability of large quantities of blood and the various clotting factors that may be necessary in some patients. In addition, arteriography must be available constantly and on a moment's notice, because it is often necessary in making the diagnosis. Finally, a good intensive care unit with skilled respiratory therapists is mandatory in handling the complications of this type of operation. Many such patients have had at least one myocardial infarction before operation on the aorta and many of the complications will lead to massive distension of the abdomen with high diaphragm, atelectasis, and the need for continual respiratory care if the patient is to survive.

Animals↗
PubMed1975

Qualitative and quantitative determinations of acid phosphatase activity in vaginal washings.

In the absence of spermatozoa, acid phosphatase activity (ACP) is an indicator of seminal fluid in cases of sexual assault. Both qualitative and quantitative ACP methods are employed by medical examiners. A large series of cases in which a qualitative test was employed is reported. A method for obtaining and handling specimens by vaginal washing was developed. This method provides suitable specimens for the examination for spermatozoa and the determination of ACP. Specimens obtained from 41 women provided examples of endogenous vaginal ACP and intravaginal seminal ACP. These specimens were used to evaluate qualitative and quantitative ACP methods for the detection of seminal ACP. Tartrate inhibition was not useful for separating endogenous vaginal and seminal ACP activities. The advantages of the method developed for specimen acquisition and of quantitative assays for ACP are discussed.

Acid Phosphatase↗
PubMed1975

Clostridium sordelli infection.

A case of human Clostridium sordelli soft tissue infection is presented. Analysis of this patient's course led to the use of a mouse experimental model for examination of this organism's potential for toxin production. Data thus obtained correlated with that seen in this instance of human infection, indicates that the lethal effects of this organism may be related to the ability to Clostridium sordelli to produce a widespread "toxin-mediated" edema with subsequent marked "third-space" sequestration of fluid.

Adult↗
PubMed1975

SCUBA tank corrosion as a cause of death.

Corrosion of compressed air breathing tanks may result in dangerous oxygen depletion. In every SCUBA mishap the residual air should have, as one of the tests, a measurement of oxygen content. The tank should also have a visual inspection. All compressed air breathing tanks should have a routine visual inspection on a regular basis, even if the tank is made or lined with corrosion resistant material.

Accident Prevention↗