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Biomedical subjects

J Freeman

Publications and source records attributed to J Freeman.

At least 73 records · Page 4Linked to original sources
PubMed1988

Changes in CSF pressure after mannitol in patients with and without elevated CSF pressure.

In view of the current concern that rapid infusion of mannitol might initially aggravate intracranial hypertension, the effects of a mannitol infusion on lumbar cerebrospinal fluid pressure (CSFP) were investigated in 49 patients. The studies were performed when the patients were under general anesthesia prior to elective craniotomy for tumor resection or intracerebral aneurysm clipping. The patients were divided into two groups: 24 patients with normal CSFP (Group I, mean CSFP 10.5 mm Hg) and 25 with raised CSFP (Group II, mean CSFP 20.8 mm Hg). Measurements of CSFP, mean arterial blood pressure (MABP), and central venous pressure (CVP) were made serially during and after the infusion of 20% mannitol (1 gm.kg-1 infused over a 10-minute interval). In both groups, mannitol infusion provoked a fall in MABP and an increase in CVP. An immediate decrease [corrected] in CSFP was observed in Group II, whereas CSFP increased transiently but significantly in Group I. Analysis of the arterial and venous driving pressures which contribute to CSFP suggests that the transient increase in CSFP after mannitol in Group I was partly due to the increase in CVP. The presence of intracranial hypertension may thus alter the CSFP response to arterial and venous pressure changes. Cerebral blood volume (CBV) was measured in dogs in a separate study analogous to the human protocol. The CBV increased approximately 25% over control values after mannitol infusion both in the normal animals and in those with CSFP raised by an epidural balloon. The response of the CSFP to mannitol infusion differed between both groups in a fashion similar to that observed in the human subjects. Thus, differences in CBV changes after mannitol do not account for the difference in CSFP response between normal subjects and those with raised CSFP.

Animals↗
PubMed1988

Mandibulotomy and radical radiotherapy: compatible or not?

The mandibular swing, as an approach to upper aerodigestive tract malignancies, has been gaining popularity in recent years. Little has been reported in the literature as to the feasibility of this procedure in subjects having received radical preoperative radiotherapy. The preliminary results of a retrospective analysis of 23 subjects, 70% of whom received radical preoperative radiotherapy, is presented. There was no statistically significant difference between the complication rates in the irradiated and nonirradiated subject populations. All subjects, ultimately, were orally rehabilitated.

Adult↗
PubMed1987

Coagulase-negative staphylococcal bacteremia in the changing neonatal intensive care unit population. Is there an epidemic?

A fivefold increase in the number of cases of nosocomial coagulase-negative staphylococcal bacteremia was investigated in a neonatal intensive care unit between 1975 and 1982. This apparent outbreak was not the result of increased isolation of coagulase-negative staphylococci from blood cultures nor an increased frequency with which blood cultures were obtained. Rather, it was attributable to a dramatic increase in the overall probability that a positive blood culture would be interpreted as "bacteremia" as opposed to a contaminant by both physicians and infection control staff. Specifically, there had been a 62.3% increase in neonatal intensive care unit bed use by very-low-birth-weight (less than 1000-g) infants between 1975 and 1982, and in both years, positive blood cultures were 3.8 times as likely to be perceived as clinically significant if obtained from such tiny infants. The growing number of very-low-birth-weight babies occupying neonatal intensive care unit beds, coupled with the observation that blood cultures positive for coagulase-negative staphylococci are almost four times as likely to be perceived as clinically significant if obtained from extremely premature infants, may account for the reported increase in nosocomial coagulase-negative staphylococcal bacteremia.

Boston↗
PubMed1987

Prevention of nosocomial respiratory syncytial virus infections through compliance with glove and gown isolation precautions.

To determine whether increased compliance with a policy of glove and gown isolation precautions could reduce the high rate of nosocomial respiratory syncytial virus (RSV) infection on an infant and toddler ward, we conducted a longitudinal intervention trial during three RSV seasons, from 1982 to 1985, with an intervention to increase compliance introduced midway through the second season. The risk of acquiring RSV infection in the hospital was adjusted for the intensity of nosocomial exposure to the virus by assigning each study week to one of five strata, defined by the proportion of hospital days on which virus was shed by children on the ward. Overall, 37 patients acquired nosocomial RSV infections during 7547 days at risk. The adjusted relative risk, comparing the infection rate in the period before the intervention (when compliance with isolation precautions was noted in only 38.5 percent of the observed patient contacts) with the infection rate in the postintervention period (when compliance more than doubled) was 2.9 (95 percent confidence interval, 1.5 to 5.7). Rates of nosocomial RSV infection increased linearly with increasing levels of exposure to patients shedding virus, but the rise in the infection rate with increasing exposure was less than one fourth as great (P less than 0.001) in the period after the intervention as it was before. We conclude that glove and gown precautions can substantially reduce the nosocomial transmission of RSV, particularly with increasing exposure to patients shedding the virus.

Cross Infection↗
PubMed1987

Ingestion of potassium permanganate crystals by a three-year-old boy.

We report a case of corrosive burns to the mouth, oesophagus and trachea in a three-year-old boy who ingested potassium permanganate crystals. The pathophysiology and treatment options are discussed. The prevention of accidental ingestion could be improved with careful packaging of the solid tablet or crystalline forms.

Acute Disease↗
PubMed1987

Percutaneous transtracheal ventilation for laser endoscopic procedures in infants and small children with laryngeal obstruction: report of two cases.

The case reports of two children with obstructive lesions of the larynx are presented to illustrate the advantages of transtracheal ventilation for paediatric endoscopic laser surgery. The first patient was a four-month-old infant with inspiratory stridor due to a subglottic haemangioma obstructing 80 per cent of the lumen. The second patient was a five-year-old child with posterior synechiae of the larynx. The anaesthetic and ventilation techniques were the same for both cases. A transtracheal catheter was introduced percutaneously into the trachea under endoscopic control and connected to a high frequency jet ventilator. The advantages of this technique during laser surgery are: clear vision of the operative field, good gas exchange, elimination of airway trauma from intubation, reduction of the hazard of airway fires, and decreased risk of aspiration of blood and debris. In addition, this method of providing oxygen and/or mechanical ventilation may be extended into the postoperative period. In certain situations, this technique can be an attractive alternative to a tracheostomy with its potentially dangerous and incapacitating complications in infants and small children.

Airway Obstruction↗
PubMed1987

Gamma-glutamyl transpeptidase activity in human oral squamous cell carcinoma.

Gamma-glutamyl transpeptidase (GGT) activity has been shown to increase in preneoplastic cells in various experimental carcinogenesis models and in some human tumors. This pilot study was undertaken to examine its potential use in detection of sites of human oral carcinogenesis. Samples were taken from 16 surgical specimens: 12 resection specimens for squamous carcinomas and 4 benign mucosal lesions. Twelve of the patients were tobacco users. Diffuse GGT activity was found in all tobacco users and heavy cellular activity in all carcinomas. In four of the carcinoma-resection specimens, occasional cells staining heavily for GGT activity were noted in epithelium distant from the tumor itself. These results are discussed in relation to the potential value of GGT activity as a marker from preneoplastic changes in oral epithelium.

Adult↗
PubMed1987

Comparisons of hospital bed utilization in Australia and the United States using DRGs.

The mean lengths of stay and discharge rates per 10,000 patients were compared for Victoria, Australia, and the United States on a DRG-specific basis to explain variations in hospital bed utilization and costs. Results were presented for a number of high-volume DRGs where the differences between the two hospital systems were substantial. For several DRGs associated with chronically ill patients, the mean lengths of stay were much longer in Victoria, although most of the difference disappeared after the removal of outliers. The presence of many acute-care patients in Victoria in several DRGs associated with minor surgical procedures produced very low mean lengths of stay. In the United States, rates were markedly higher for providing several major elective surgical procedures and very high-volume medical DRGs. The results of this comparison indicate that greater control over admission and discharge practices could promote greater efficiency and higher quality care in both Australia and the United States.

Australia↗
PubMed1987

Confounding and the analysis of multiple variables in hospital epidemiology.

Most information in hospital epidemiology comes from observational studies of hospitalized patients rather than planned experiments, and in such observational studies the characteristics of study patients may vary widely, even within a single hospital. Any comparison between hospital populations will usually contain additional, unintended contrasts among patients with varying degrees of health. Adult patients, for example, may have vastly different underlying diseases, and infants may be of substantially different birth weights. We used both underlying disease and birth weight as indices of the basic severity of illness in order to adjust for confounding by differences in underlying disease in reanalyses of several published studies. We give an example in which differing birth weights among groups of infants compared artifactually double the apparent effect of nosocomial infections as a cause of mortality, and another example in which differing degrees of severity of underlying illness artifactually halve the apparent effect of appropriate antibiotics in preventing death from bacteremia with gram-negative bacilli. We describe simple intuitive methods based on stratification, adapted from chronic disease epidemiology, to remove confounding effects during analyses.

Birth Weight↗
PubMed1987

Accelerated idioventricular rhythm during flexible fiberoptic bronchoscopy.

We report the case of a patient who developed severe hypoxemia and an unusual arrhythmia, accelerated idioventricular rhythm, during flexible fiberoptic bronchoscopy. Coronary artery disease was subsequently suspected despite an unremarkable history and physical examination, and confirmed by a thallium 201 imaging. The appearance of accelerated idioventricular rhythm during fiberoptic bronchoscopy should raise the possibility of underlying coronary artery disease.

Aged↗
PubMed1987

Hypernatraemia due to a reset osmostat for vasopressin release and thirst, complicated by nephrogenic diabetes insipidus.

We describe a patient with chronic hypernatraemia (plasma sodium 148-155 mmol/l) and partial nephrogenic diabetes insipidus who had received prolonged lithium treatment. Despite stopping the drug for one year the abnormalities remained. Infusion of hypertonic saline (NaCl 855 mmol/l) allowed the characterization of osmoregulation of thirst and vasopressin secretion. Linear regression analysis of plasma vasopressin and osmolality defined the function, pAVP = 0.27 (pOsm - 301), and analysis of thirst measured by a visual analogue scale and plasma osmolality, the function, thirst = 0.16 (pOsm - 302) where pAVP and pOsm represent plasma arginine vasopressin and osmolality respectively. The slopes of the regression lines which describe the sensitivity of the osmoreceptors were within the normal range, but both abscissal intercepts, which define the thresholds for vasopressin release and thirst, were markedly elevated in comparison to normal (upper limit less than 290 mOsm/kg). Other investigations of electrolytes, anterior pituitary function and high definition computed tomographic scanning of hypothalamo-pituitary region were all normal. We conclude that this patient's chronic hypernatraemia was due to resetting of the osmostats for both vasopressin release and thirst, a rarely described mechanism to account for hypernatraemia. Although it is probable that the partial nephrogenic diabetes insipidus was related to prolonged lithium therapy, the cause of the reset osmostats remains unclear.

Aged↗
PubMed1987

Myocardial injury after electrical burns: short and long term study.

Miscellaneous cardiac abnormalities can occur after electrical burns. The long term outcomes are still unknown. We studied 10 patients, 9 of whom suffered high-voltage electrocution, and one of whom was struck by lightning. Serial electrocardiograms (ECG) and serum MB creatine phosphokinase isoenzyme (MB-CPK) activities were obtained during their stay in hospital. ECG and thallium 201 cardiac scintigraphy at rest, as well as echocardiograms were obtained in all patients 4 to 48 months after discharge. In hospital, 9 patients showed one or more abnormal findings at physical examination (4 cases), ECG (8 cases), MB-CPK (1 case). At long term follow-up, 5 patients had one or more myocardial functions or conduction abnormalities, with or without symptoms. One patient had compensated heart failure. Nine patients were asymptomatic. Abnormal ECG findings persisted in 3 patients. Three cardiac scans showed evidence of regional myocardial hypoperfusion. Decreases in left ventricular indices measured by echocardiogram were found in 3 patients. We conclude that high-voltage electrocution is associated with a high incidence of cardiac abnormalities, which may persist. Long term evaluation, requiring cardiac T1 201 scintigraphy and echocardiogram, may be justified.

Adult↗
PubMed1987

Novel nucleolar antigens in autoimmune disease.

Antinucleolar antibodies are of interest in 2 important areas, namely, autoimmune diseases and specific products involved in the "mitogenic cascade." The former have delineated a series of novel nuclear and nucleolar elements including the recently described proliferating cell nuclear antigens (PCNA), some of which are present in the nucleolus only at specific times in the G1-S phase of the cell cycle. Important new proteins such as "fibrillarin" (34 kD/pI 8.5) and a 125 kD nucleotide containing protein have been identified with antinucleolar antibodies. Protein p145 is a nucleolar PCNA that is present in growing and dividing cells but not in normal resting tissues. Antinucleolar antibodies offer powerful tools, not only for identification of specific nucleolar proteins important in the cell cycle, but also for purification of their genes and analysis of mechanisms of gene control that operate the "time windows" of the cell cycle.

Amino Acid Sequence↗
PubMed1987

Radiologic artifact.

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Administration, Cutaneous↗