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Biomedical subjects

J C Walsh

Publications and source records attributed to J C Walsh.

At least 37 records · Page 2Linked to original sources
PubMed1994

Risk factors associated with pulmonary embolism despite routine prophylaxis: implications for improved protection.

Despite prophylaxis, pulmonary embolism (PE) remains a major cause of posttraumatic morbidity and mortality in high-risk patients. We studied injury-related risk factors associated with the occurrence of PE despite routine prophylaxis. A review of 9721 trauma patients discharged from January 1, 1985 through December 31, 1992, identified 36 patients (0.4%) who suffered clinically evident PE despite a policy of routine prophylaxis against deep venous thrombosis that included use of prophylactic inferior vena caval filters. (Twenty-nine patients had an inferior vena caval filter placed for prophylaxis against PE.) A detailed analysis of injury-related risk factors was performed. Four high-risk patterns of injury were identified, representing common combinations of significant risk factors. These patient groups have an absolute risk of PE despite prophylaxis ranging from 1.5% to 3.8%. The relative risk is approximately ten times that of control patients. Identification of appropriate high-risk groups is necessary to allow optimization of prophylactic measures, including placement of inferior vena caval filter.

Adult↗
PubMed1994

The economic status of trauma centers on the eve of health care reform.

An in-depth understanding of the economic problems confronting trauma centers is essential for their continued development and to address impending changes of health care reform. A comprehensive financial and demographic survey was sent to 839 hospitals identified as potential trauma centers. A total of 313 surveys from 48 states were returned. Extensive information was collected in several areas including financial status (58% reported serious financial problems and 36% reported minor financial problems; 68% reported a financial loss), cost containment and management strategies, marketing, "halo" effect (53% reported positive effect), operational impacts, physician support (47% reported problems), malpractice (92% reported no special problem), role of auto insurance reimbursement, and access to rehabilitation. Detailed financial data of actual costs and reimbursements (95 respondents) were analyzed with the costing method used by the Health Care Financing Administration (HCFA). These data will allow us to develop better strategies to deal with the problems of uncompensated and underfunded trauma care and improve trauma center viability.

Catchment Area, Health↗
PubMed1991

A comparison of hypertonic to isotonic fluid in the resuscitation of brain injury and hemorrhagic shock.

We studied the early and late effects of hypertonic resuscitation (HR) on the injured brain using a porcine model of hemorrhagic shock and focal cryogenic brain injury. After shock, swine were randomly assigned to receive a bolus (4 cc/kg) of either Ringers lactate (RL) or 7.5% hypertonic saline in 6% Dextran 70, followed by either RL or hypertonic sodium lactate to restore mean arterial pressure to baseline. All animals were studied for 24 hr after the start of resuscitation. Bolus HR improved cerebral blood flow (CBF) with a lower intracranial pressure (ICP) than RL. Continued hypertonic resuscitation prolonged the period of improved CBF and low ICP. At 24 hr CBF had deteriorated in the region of injury in all study groups and in the uninjured hemisphere in swine receiving RL. These data suggest that rapid resuscitation without increasing ICP for up to 6 hr as seen with hypertonic fluid could conceivably allow adequate time for surgical evacuation of mass lesions and effectively prevent secondary brain injury. This work underscores the importance of prolonged periods of study when evaluating brain resuscitation from traumatic shock.

Animals↗
PubMed1991

Resuscitation of hypovolemic sheep with hypertonic saline/Dextran: the role of Dextran.

We evaluated the role Dextran-70 plays in small volume resuscitation of hemorrhage using hypertonic saline dextran solutions. Sheep were hemorrhaged (1.5 to 2 liters) over 2 hr to an arterial pressure of 50 mm Hg and were then resuscitated with 100 ml of either 7.5% NaCl (HS/0% Dex) alone, 7.5% NaCl/6% Dextran-70 (HS/6% Dex), or 7.5% NaCl/24% Dextran-70 (HS/24% Dex). During hemorrhage cardiac output was reduced to 40-50% of baseline levels. The major effect of the added dextran was a greater initial increase and more sustained normalization of plasma volume and cardiac output. At 15 min post-infusion, plasma volume was expanded 17 +/- 2% with HS/0% Dex; 27 +/- 2% with HS/6% Dex; and 56 +/- 8% with HS/24% Dex. A dose response effect of the added dextran was also apparent in the post-resuscitation increases in arterial pressure and cardiac output. At 3 min post-infusion, both variables improved with all solutions, but baseline levels were reached and exceeded only in the HS/24% Dex. The increased cardiac output correlated significantly with the degree of vascular expansion. Regression and extrapolation of the post-resuscitation data of plasma volume expansion and increased cardiac output to no volume expansion suggests that the hypertonic saline also augments cardiac output by an additional mechanism independent of volume. Our data show that the addition of dextran to hypertonic saline can play an important role in small volume hypertonic resuscitation by improving both the initial cardiovascular response and the sustainment of that response. Higher concentrations of dextran than currently used in hypertonic formulations may make small volume resuscitation more efficacious.

Animals↗
PubMed1990

The effects of aortic crossclamping and resuscitation on intracranial pressure, cerebral blood flow, and cerebral water content in a model of focal brain injury and hemorrhagic shock.

Aortic crossclamping (AOXC) is performed frequently in hypotensive trauma patients who may have had a head injury. The effect of AOXC on the injured brain is unknown. We studied the effect of AOXC on mean arterial pressure (MAP), intracranial pressure (ICP), cerebral blood flow (CBF), cerebral perfusion pressure (CPP), and cerebral water content in a porcine model of focal cryogenic brain injury. Four groups of animals were studied: Group I--brain injury only; Group II--brain injury and AOXC; Group III--brain injury with hemorrhage and AOXC; and Group IV--AOXC only. Focal cryogenic grain injury increased the ICP in Groups I-III. Aortic crossclamping increased MAP, CBF, ICP, and CPP after hemorrhage in Group III. Following declamping and resuscitation there were no differences between the groups in any studied variable. Cerebral water content at the site of the focal brain injury was greater than in nonlesioned cortex but there was no significant difference between groups despite a greater positive fluid balance in hemorrhaged animals. AOXC improved perfusion to the injured brain without a significant increase in ICP. Increased MAP induced by AOXC and large fluid resuscitation appeared to have no detrimental effect on ICP, CBF, cerebral water content, or CPP in this model of brain injury.

Animals↗
PubMed1990

Lack of late toxicity in patients treated with cisplatin-containing combination chemotherapy for metastatic testicular cancer.

To date, the prevalence and nature of the late toxicity of cisplatin-based combination chemotherapy for advanced testicular cancer has been poorly documented. Thirty men with a median age of 35 years (range, 23 to 63), who had undergone such treatment were assessed with detailed investigation to determine the type and frequency of chronic toxicity. The median follow-up from the time of commencement of chemotherapy was 75 months (range, 48 to 126). The most common late toxic effects were high tone hearing loss in 23 men (77%) and electrophysiological evidence of peripheral nerve damage in 15 (50%). Both the hearing and nerve abnormalities were predominantly asymptomatic. In addition, elevation of serum cholesterol, noted in 20 patients (67%), was significant (P = .014) when compared with a control population. Hyperuricemia was present in nine patients (30%). Only one patient, with other risk factors (smoking, family history), had evidence of ischaemic heart disease while 20% (all with a smoking history) had a diminished single breath diffusing capacity for carbon monoxide (DLCO). Cisplatin-based chemotherapy is relatively free of major long-term side effects and should not be withheld for fear of late toxicity.

Adult↗
PubMed1989

Comparison of hypertonic saline/dextran versus hypertonic saline/hetastarch for resuscitation of hypovolemia.

In the present study, we compare resuscitation of bled sheep with hypertonic saline/dextran or hypertonic saline/hetastarch. Unanesthetized sheep were subjected to 2 h of hemorrhagic hypotension and then resuscitated with 200 ml of 7.5% NaCl solution made up to include either 6% dextran 70 (Macrodex) or 6% hetastarch (Hespan). Both solutions provided an immediate and sustained improvement in arterial pressure and cardiac output. The hypertonic saline/dextran provided a slightly better overall response as mean arterial pressure, cardiac output and central venous pressure were higher in the dextran group at all times post resuscitation. However, only the differences in arterial pressure and initial plasma volume expansion were statistically significant. The somewhat better response to hypertonic saline/dextran may be explained by the higher oncotic pressures generated by dextran compared to equal concentrations of hetastarch.

Animals↗
PubMed1989

Resuscitation of hemorrhage with intraosseous infusion of hypertonic saline/dextran.

We resuscitated unanesthetized bled sheep (bled volume = 1.2-1.7 liters) with 200 ml of hypertonic saline/dextran 70 infused either through a peripheral vein (n = 6) or directly into the red marrow of the sternum (n = 6). Intraosseous infusion of the viscous 7.5% NaCl/6% dextran solution required 2-4 min. Plasma sodium was rapidly increased to the same level in both groups demonstrating equally rapid entry into the vascular space. Both regimens provide rapid and sustained normalization of arterial pressure and cardiac output. No significant differences between the two groups were apparent for any measured variable. Intraosseous infusion of hypertonic resuscitation fluids merits further research to evaluate the safety and efficacy for prehospital treatment of hypovolemia and trauma.

Animals↗
PubMed1987

Surgical management of subclavian artery injury.

During a 10 year period, we have had operative experience with 13 injuries to the subclavian artery. The factors that led to the successful management in 10 consecutive patients were analyzed. Nonspecific signs, such as pain and swelling, were present in all of the patients. Some aspect of vascular injury was present in each patient and included change in the quality of the distal pulse, hematoma, active hemorrhage, and bruit. Roentgenologic signs such as lung opacification, fractured clavicle, fracture of the first or second rib, and pulmonary opacification were present in each patient. Arteriograms were obtained from all stable patients in whom this injury was suspected. There were no false-positive or false-negative findings. The operative approach for the right subclavian vessels was midline sternotomy, whereas for exposure of proximal left subclavian injuries, anterolateral thoracotomy was utilized. Claviculectomy permitted excellent exposure for distal subclavian artery injuries. This exposure was associated with minimal blood loss and permitted direct repair of complex injuries of the arteries and veins. All patients who reached the emergency room with measurable vital signs survived, and all those who underwent subclavian vascular repair had circulation restored. Principal morbidity was due to associated brachial plexus and lung injuries. A high index of suspicion, rapid transportation, aggressive resuscitation, and proper surgical exposure and repair are essential for the successful management of these rare vascular injuries.

Adult↗
PubMed1987

Variability on serial testing of pattern reversal visual evoked potential latencies from full-field, half-field and foveal stimulation in control subjects.

The change in pattern reversal visual evoked potential (PRVEP) latency over time (test-retest variability, TRV) was assessed in 30 (16 males, 14 females) adult control subjects using full-field (FF), half-field (HF) and foveal (central-field, CF) stimulation. The mean test-retest interval (TRI) was 20.5 months with a range of 18-21.5 months. There were no significant test-retest latency differences in either sex and furthermore there were no significant inter-sex differences in any of the test-retest parameters. Because of the latter finding the test-retest upper limit of normal for each parameter as defined by the mean value + 2.5 S.D. was taken as the largest value obtained in either sex. Thus the test-retest upper limits of normal for absolute latency from FF, right HF, left HF and CF stimulation were 6, 7, 9 and 7 msec, respectively; for interocular latency differences (ILD) from FF and CF stimulation were 4 and 5 msec respectively; and for right HF to left HF intraocular latency difference (IOLD) was 7 msec. It is concluded that the TRV was sufficiently small in our control group with each of the stimulus techniques to make all of them potentially useful in serial PRVEP studies. Furthermore the extra information provided by CF and HF stimulation may increase the sensitivity and accuracy with which change can be monitored.

Adult↗
PubMed1987

Estrogen enhancement of androgen-induced renal growth in the male rat.

17 beta-estradiol enhances dihydrotestosterone-induced growth of the castrate male rat kidney by increasing cell number, cell size and tissue water retention. No estrogen enhancement was observed in sex accessory tissues or other organs. This estrogen enhancement of androgen-induced growth is discussed in relation to species and organ specificity.

Animals↗
PubMed1987

Hygromycin A, an antitreponemal substance. I. Screening method and therapeutic effect for Treponema hyodysenteriae-caused infection in CF-1 mice.

In vitro and in vivo screening methods were established for the discovery of new active substances against Treponema hyodysenteriae. During the screening methods, hygromycin A produced by Streptomyces hygroscopicus KA-355 was found to be active against T. hyodysenteriae. Hygromycin A did not show high antitreponemal activity in in vitro test using the paper disc method on the agar plate inoculated with T. hyodysenteriae. However, the antibiotic exhibited highly therapeutic effect in CF-1 mice, compared with of lincomycin, tiamulin, lankacidin C or olaquindox drinking water. The effective dose (ED50) of hygromycin A was 1.1 micrograms/ml.

Administration, Oral↗
PubMed1987

Hygromycin A, an antitreponemal substance. II. Therapeutic effect for swine dysentery.

This study was conducted to evaluate hygromycin A fed to growing swine at 1, 5, 10 or 20 g/ton feed for the control of Treponema hyodysenteriae-caused dysentery. Pigs provided carbadox at 50 g/ton feed served as an infected treatment control group. All pigs were orally, via stomach intubation, administered 100 ml of a T. hyodysenteriae broth culture. During the in vivo test, rectal swabs were taken for T. hyodysenteriae isolation, body weights of all pigs and the feed consumption was determined. All pigs were euthanized and necropsied at study end; the large intestine was cultured for T. hyodysenteriae and gross intestinal lesions were noted. T. hyodysenteriae-caused swine dysentery was successfully controlled by feeding hygromycin A at 5 g/ton. Hygromycin A medicated pigs performed as well as or better than carbadox-medicated pigs.

Animals↗
PubMed1986

The application of prolonged electroencephalographic monitoring and video recording to the diagnosis of epilepsy.

This study reports the results of the application of intensive monitoring by electroencephalogram (EEG) combined with video recording as an aid to the diagnosis of epilepsy. A group of 622 patients was investigated; useful information was obtained in approximately 50% of these patients. Ten per cent of the patients with suspected epilepsy had a seizure during the period of recording. The combined analysis of the video recording and the EEG provided valuable evidence in the analysis of complex partial seizures and highlights the high prevalence of pseudoseizures in patients who are suspected of having epilepsy.

Adolescent↗
PubMed1986

Visual evoked responses and ophthalmological examination in optic neuritis. A follow-up study.

Ophthalmological examination and visual evoked responses (VERs) were repeated at 6-120 (mean 46) months after the first attack of acute optic neuritis in 80 patients who had abnormal VERs in 98 symptomatic eyes at the initial examination. The wide field VER returned to within the normal range in 19/98 (19%) symptomatic eyes. Fifteen percent of patients had completely normal VERs at follow-up. The yield of VER abnormalities was increased by the use of central field in addition to wide field stimulation. One or more components of the ophthalmological examination were abnormal in 91% of symptomatic eyes at final review. Although the ophthalmological examination was a more sensitive index than the VER of past optic neuritis in symptomatic eyes, the reverse was the case in asymptomatic eyes.

Acute Disease↗
PubMed1986

Acute optic neuritis: a prospective study of risk factors for multiple sclerosis.

Eighty two patients with isolated optic neuritis were studied prospectively to determine the frequency with which multiple sclerosis developed and the factors which increased its risk. Patients were followed for 6 to 264 months (mean, 57 months). Twenty six patients (32%) developed clinically definite or probable multiple sclerosis during the period of follow-up. Actuarial analysis predicted that 42% would develop multiple sclerosis by 7 years. Of those patients who developed multiple sclerosis, 92% had symptoms within 4 years of the first attack of optic neuritis. The highest incidence of multiple sclerosis occurred in the 21-40 year age group. There was an increased risk of MS in patients with HLA-DR2 and HLA-B7 tissue types. The frequency of HLA-DR4 was increased in patients with optic neuritis alone compared to controls and to patients with multiple sclerosis, but further studies are required to confirm this finding.

Acute Disease↗