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Biomedical subjects

M A Schreiber

Publications and source records attributed to M A Schreiber.

At least 19 recordsLinked to original sources
PubMed2005

Mortality from isolated civilian penetrating extremity injury.

BACKGROUND: Although studies have ascertained that ten percent of soldiers killed in battle bleed to death from extremity wounds, little data exists on exsanguination and mortality from extremity injuries in civilian trauma. This study examined the treatment course and outcomes of civilian patients who appear to have exsanguinated from isolated penetrating extremity injuries. METHODS: Five and 1/2 years' data (Aug 1994 to Dec 1999) were reviewed from two Level I trauma centers that receive 95% of trauma patients in metropolitan Houston, TX. Records (hospital trauma registries, emergency medical system (EMS) and medical examiner data) were reviewed on all patients with isolated extremity injuries who arrived dead at the trauma center or underwent cardiopulmonary resuscitation (CPR) or emergency center thoracotomy (ECT). RESULTS: Fourteen patients meeting inclusion criteria were identified from over 75,000 trauma emergency center (EC) visits. Average age was 31 years and 93% were males. Gunshot wounds accounted for 50% of the injuries. The exsanguinating wound was in the lower extremity in 10/14 (71%) patients and proximal to the elbow or knee in 12/14 (86%). Ten (71%) had both a major artery and vein injured; one had only a venous injury. Prehospital hemorrhage control was primarily by gauze dressings. Twelve (86%) had "signs of life" in the field, but none had a discernable blood pressure or pulse upon arrival at the EC. Prehospital intravenous access was not obtained in 10 patients (71%). Nine patients underwent ECT, and nine were initially resuscitated (eight with ECT and one with CPR). Those undergoing operative repair received an average of 26 +/- 14 units of packed red blood cells. All patients died, 93% succumbing within 12 hours. CONCLUSION: Although rare, death from isolated extremity injuries does occur in the civilian population. The majority of injuries that lead to immediate death are proximal injuries of the lower extremities. The cause of death in this series appears to have been exsanguination, although definitive etiology cannot be discerned. Intravenous access was not obtainable in the majority of patients. Eight patients (57%) had bleeding from a site that anatomically might have been amenable to tourniquet control. Patients presenting to the EC without any detectable blood pressure and who received either CPR or EC thoracotomy all died.

Adolescent↗
PubMed2001

Development and validation of a cholate binding capacity method for DMP 504, a bile acid sequestrant.

DMP 504, a highly cross-linked insoluble polymer, is a bile acid sequestrant developed by the DuPont Pharmaceuticals Company for serum cholesterol reduction. Since DMP 504 is insoluble, it was necessary to develop unique specific analytical methods to measure and control the quality of different lots of the drug. Since the mechanism of action of DMP 504 is believed to be by sequestration of bile acids, the in-vitro binding capacity of the polymer for cholic acid was chosen as a surrogate of in-vivo performance and used to assess potency of the compound. In this method, individual aliquots of DMP 504 at three different levels were incubated with a cholate solution of known concentration. The residual cholate solution was filtered and analyzed by a reversed-phase HPLC method using refractive index detection. When the bound cholate was plotted versus the mass of DMP 504, the resulting curve was linear. The slope of this curve is the cholate binding capacity of DMP 504. This method has been shown to be precise and robust. Precision of the method was shown to have an RSD of 2.0% with injection precision of 0.4% and stability of cholate solutions up to 73 h. It is also a unique binding capacity method due to its multi-point determination, and it has been shown to be a suitable quality control method for ensuring lot-to-lot consistency of drug substance.

Cholates↗
PubMed2000

Predictive model for survival at the conclusion of a damage control laparotomy.

BACKGROUND: We employed modern statistical and data mining methods to model survival based on preoperative and intraoperative parameters for patients undergoing damage control surgery. METHODS: One hundred seventy-four parameters were collected from 68 damage control patients in prehospital, emergency center, operating room, and intensive care unit (ICU) settings. Data were analyzed with logistic regression and data mining. Outcomes were survival and death after the initial operation. RESULTS: Overall mortality was 66.2%. Logistic regression identified pH at initial ICU admission (odds ratio: 4.4) and worst partial thromboplastin time from hospital admission to ICU admission (odds ratio: 9.4) as significant. Data mining selected the same factors, and generated a simple algorithm for patient classification. Model accuracy was 83%. CONCLUSION: Inability to correct pH at the conclusion of initial damage-control laparotomy and the worst PTT can be predictive of death. These factors may be useful to identify patients with a high risk of mortality.

Critical Illness↗
PubMed2000

Trauma patient outcome in an army Deployable Medical Systems environment compared with a medical center.

William Beaumont Army Medical Center is the second busiest trauma center in the Army. Recent facility renovations there necessitated the use of a temporary field hospital to serve as the Emergency Department, which included the initial evaluation and resuscitation of trauma patients by the trauma team. Although designed for the battlefield, the use of field medical equipment during renovation of military medical facilities is not a new concept. The MUST (Medical Unit Self-contained Transportable) and DEPMEDS (Deployable Medical Systems) have been used successfully during fixed-facility renovations. Previously described functions included inpatient services, outpatient care, and operating room facilities. However, no published information directly compares the use of these temporary structures with standard fixed facilities in the initial management of trauma patients. Trauma patients often present with complex concerns, are highly resource intensive, and their survival is dependent on efficient, timely care. We compared several aspects of patient outcome in the DEPMEDS versus the medical center.

Adolescent↗
PubMed2000

Military assistance to safety and traffic services in El Paso: a retrospective analysis.

This study was performed to evaluate the performance of military rotary air medical transport in the El Paso, Texas, region with regard to mortality. A retrospective review of transport and inpatient medical records was undertaken. All trauma patients air transported from January 1, 1996, to February 28, 1998, were included. Patients for whom records were unavailable were excluded. Mean time intervals for prehospital and interhospital transport were calculated. Injury severity and survival data were calculated using Revised Trauma Score, Injury Severity Score, and Trauma and Injury Severity Score (TRISS) methodology. Two hundred sixty-seven patients were eligible for analysis (83% of the total). TRISS analysis predicted 241 survivors; the actual number of survivors was 241 (mean = 0.98, z = 0.03) despite the fact that 6 individuals died who were predicted to live and 3 individuals lived who were predicted to die. We conclude that the actual mortality rate of those patients transported by military aeromedical lift equaled that predicted by TRISS methodology.

Air Ambulances↗
PubMed1998

Effect of inline filtration on ViaSpan cold-storage solution.

The effect of filtration on the particulate load in ViaSpan cold-storage solution was studied. Commercially available inline blood transfusion filters (SQ40S, Pall Biomedical) were inserted into the delivery-set port of polyvinyl chloride bags of ViaSpan (DuPont Merck Pharmaceutical). Particles in samples collected in particle-free vials before and after filtration were counted by a light-obscuration technique. The compatibility of key ViaSpan ingredients and of three commonly used additives (penicillin G potassium, dexamethasone sodium phosphate, and human insulin) with the inline filter was also investigated. Filtration removed 56% of particles 5-10 microm in diameter, 71% of particles of > 10-25 microm, and > 99% of particles measuring > 25 microm. Flow rates with the filters were more than adequate for clinical use. Concentrations of constituent hydroxyethyl starch, glutathione, adenosine, allopurinol, raffinose pentahydrate, and lactobionic acid were not significantly affected by filtration, nor were the concentrations of any of the drug additives. Inline filtration of ViaSpan effectively reduced fatty acid salt particulates in the solution and had no deleterious effect on flow rate, ingredient concentrations, or concentrations of commonly added drugs.

Adenosine↗
PubMed1998

Femoral venous flow dynamics during intraperitoneal and preperitoneal laparoscopic insufflation.

BACKGROUND: Laparoscopic herniorrhaphy may be performed using an intraperitoneal or a preperitoneal approach. Anecdotal and experimental evidence indicates that alterations in lower extremity venous flow, which occur during intraperitoneal laparoscopic insufflation, may be associated with an increased risk of deep vein thrombosis. However, no study has directly compared femoral venous flow during intraperitoneal insufflation with that during preperitoneal insufflation. METHOD: In eight consecutive patients undergoing laparoscopic herniorrhaphy under general anesthesia, flow through the common femoral vein was evaluated with B-mode and color flow duplex. Pre- and intraperitoneal pressures were standardized to 10 mm Hg, and respiratory tidal volumes were standardized to 10 cc/kg. Flow measurements were taken at end expiration. Flow through the common femoral vein was measured after induction of anesthesia, during intraperitoneal insufflation, during preperitoneal insufflation, and between insufflations to ensure return to baseline. RESULTS: All patients in the study were males. Their mean age was 59 years. Mean flow in the common femoral vein was essentially identical at baseline (138 ml/min) and during preperitoneal insufflation (135 ml/min). Alternatively, mean flow in the common femoral vein was significantly reduced during intraperitoneal insufflation (65 ml/min, p = 0.02). CONCLUSIONS: Flow in the common femoral vein is significantly reduced during intraperitoneal insufflation. However, flow in the common femoral vein is not affected by preperitoneal insufflation. These data suggest that laparoscopic preperitoneal inguinal hernia repair may pose as less a risk of thromboembolic complications than laparoscopic intraperitoneal inguinal hernia repair.

Adult↗
PubMed1998

Timing of vaccination does not affect antibody response or survival after pneumococcal challenge in splenectomized rats.

BACKGROUND: Pneumococcal vaccination after splenectomy for trauma decreases the incidence of overwhelming postsplenectomy infection. The optimal timing of vaccination has not been established. This study was conducted to determine whether timing of vaccination after splenectomy affects antibody response or survival after pneumococcal challenge. METHODS: Sprague-Dawley rats were used for all experiments. Control rats (n=30) were divided into three equal groups and underwent splenectomy followed by sham vaccination 1, 7, or 42 days after splenectomy. Treated rats (n=66) were divided into three equal groups and underwent splenectomy followed by vaccination with polyvalent pneumococcal vaccine 1, 7, or 42 days after splenectomy. All rats then underwent intraperitoneal Streptococcus pneumoniae inoculation with the predetermined lethal dose for 50% of the population 10 days after vaccination. Rats were observed for a 72-hour period after inoculation, and mortality was recorded. Immunoglobulin G and immunoglobulin M antibody titers were determined before vaccination and before inoculation to determine antibody response. RESULTS: Mortality was greater in the control group than in the treatment group (21 of 30 [70%] vs. 2 of 64 [3%]; p < 0.01). There were no differences in mortality within either the control group (1 day, 6 of 10; 7 days, 7 of 10; 42 days, 8 of 10; p=0.62) or the treatment group (1 day, 0 of 21; 7 days, 0 of 21; 42 days, 2 of 22; p=0.14). Immunoglobulin G and immunoglobulin M antibody responses were greater in vaccinated than in nonvaccinated rats. There was no effect of timing of vaccination on antibody response. CONCLUSION: Pneumococcal vaccine reduces mortality from postsplenectomy infection. Timing of vaccination after splenectomy does not affect survival from a pneumococcal challenge or antibody response in rats. This study supports the practice of administering vaccine within 24 hours of splenectomy when vaccine cannot be administered before surgery.

Animals↗
PubMed1997

Quantitation and determination of molecular weight distribution of residual water soluble extractable polyamines in DMP 504, a poly-alkylamine bile acid sequestrant, by aqueous high performance size exclusion chromatography.

A high performance size exclusion chromatography (HPSEC) method with refractive index detection for quantitation and molecular weight determination of extractable water soluble polyamines (SPA) in a novel proprietary polymeric pharmaceutical compound (DMP 504) is described. The extracted polyamines are synthetic impurities as well as potential degradation products of the polymer. Data for calibration, precision, solution stability, and limits of detection and quantitation are presented to validate the suitability of this method for its intended purpose. Response linearity for the poly(2-vinylpyridine) standard is demonstrated between 10 and 1000 micrograms ml-1, equivalent to 0.005% and 0.5% (w/w) in DMP 504. Molecular weight distributions of SPA extracted from DMP 504 are presented. No increase in SPA is detected in DMP 504 over 6 months storage at room temperature.

Calibration↗
PubMed1996

Limiting computed tomography to patients with peritoneal lavage-positive results reduces cost and unnecessary celiotomies in blunt trauma.

OBJECTIVE: To determine if computed tomographic (CT) scanning can be used to identify patients with blunt trauma, positive results of diagnostic peritoneal lavage (DPL), and a stable hemodynamic status who could be managed safely and cost-effectively without celiotomy. DESIGN: Patients with blunt trauma who required an abdominal evaluation underwent DPL. Patients with a red blood cell count greater than 10(11)/L (10(5)/mm3) on lavage then underwent CT. Patients with solid organ injury alone, as detected on CT scan, were observed; those with evidence of hollow viscus injury underwent celiotomy. RESULTS: Sixty-seven hemodynamically stable patients had a red blood cell count greater than 10(11)/L on DPL; 38 patients underwent subsequent CT scanning, and 29 underwent immediate celiotomy in violation of the protocol. Eleven patients in the protocol group ultimately underwent celiotomy. Overall, there were significantly fewer nontherapeutic celiotomies performed in the protocol group (2/38 vs 9/29, P < .01). There were no deaths in either group. Because DPL is less expensive than CT, limiting CT to patients with DPL-positive results and hemodynamic stability reduced the charges associated with abdominal evaluation by $580,594 over a period of 2 years. CONCLUSION: Limiting CT to the evaluation of patients with DPL-positive results and hemodynamic stability is safe, reduces charges, and results in a lower rate of nontherapeutic celiotomies compared with DPL alone.

Abdominal Injuries↗
PubMed1993

Stepwise development of a clinical expert system in rheumatology.

The evaluation of computer expert systems, a promising diagnostic tool for future application in clinical medicine, is of great importance. We present here the evaluation of our expert system, "RHEUMA". It is stressed, that repeated retrospective testing and updating of an expert system and its subsequent repeated assessment in clinical use and surroundings is mandatory. This increases the diagnostic accuracy of the system. For our system this is demonstrated under three separate conditions. In the first study the information available for the computer system (mainframe) came from medical histories only. Here an error rate of about 25%--similar to that of physicians themselves using the same information--was observed in 358 outpatients, compared to the final diagnoses of physicians also relying solely on information from medical histories. In a second step a completely new system on a personal computer was developed with all relevant diagnostic information. The error rate of this system (0.4%) was much too optimistic because the knowledge base was changed during the study, affecting about 30% of the 282 prospectively recruited outpatients. In a third step the efficacy of the expert system was tested in an additional hospital without the diagnostic involvement of the first testing clinic. The error rate of the system without changing the knowledge base reached 11% in 51 outpatients in this rheumatology clinic. This result reflects the diagnostic accuracy of the system today. Its ability to specify the same diagnoses which clinical experts reached approached 90%. Considerable time is needed for such prospective testing, with repeated updating of the knowledge base--in our case for both the two systems and field studies of 2 years each.(ABSTRACT TRUNCATED AT 250 WORDS)

Computers↗
PubMed1993

Effects of intravenous pentafraction on lung and soft tissue liquid exchange in hypoproteinemic sheep.

Effects of infusing pentafraction (Pen), a synthetic hydroxyethyl starch plasma volume expander, on lung and soft tissue lymph flux were compared in nonanesthetized sheep that were protein depleted by batch plasmapheresis. Pen (5%) was infused to raise pulmonary arterial wedge pressure by 5 mmHg for 2 h (1.8 +/- 0.3 l). Pen raised plasma osmotic pressure from plasmapheresis baseline (10.7 +/- 2.2 mmHg; preplasmapheresis baseline, 19.6 +/- 0.6 mmHg) to 16.6 +/- 2.4 mmHg. After Pen, lung lymph flows peaked at 3.9 +/- 2.0 times a preplasmapheresis baseline value of 1.0 (plasmapheresis baseline, 2.7 +/- 0.7), but soft tissue lymph flows rose insignificantly. Plasma Pen concentrations were 2.3 +/- 1.0% postinfusion and 1.6 +/- 0.3% at 12 h. Pen mean molecular masses at these times, measured by high-performance liquid chromatography, were 160 +/- 44 and 129 +/- 23 kDa, respectively. In lung lymph, Pen concentrations were 0.8 +/- 0.6% postinfusion and 0.7 +/- 0.2% at 12 h, with mean molecular masses of 125 +/- 44 and 112 +/- 18 kDa, respectively. In soft tissue lymph Pen was nearly undetectable postinfusion, but at 12 h concentrations averaged 0.3 +/- 0.2% with a mean molecular mass of 80 +/- 10 kDa. The osmotic effectiveness of Pen may be related to its molecular mass, which was large enough to restrict filtration so that the plasma-to-lung lymph osmotic pressure gradient widened. Pen remained effective in the circulation for at least 24 h.

Animals↗
PubMed1992

Statistical geometry of pancreatic islets.

Quantitative histomorphometric studies of the dynamics of growth and development of pancreatic islets in normal and pathological states pose substantial methodological and conceptual problems. We address these problems with the geometry of random fractals, and apply our methods to the analysis of islet regeneration in the alloxan-treated guinea-pig. In both experimental islet-regenerated and control animals, islet centres are found to cluster in similar fractal subsets of dimension strictly less than 3, in agreement with the postulated origin of islets along a system of ductules, and suggesting that regeneration follows the same mathematical dynamics as original islet formation.

Alloxan↗
PubMed1992

[Assessment of risk factors and their modification in rehabilitation applicants].

Compared with the general population male workers applying for medical rehabilitation show a higher risk-load, especially regarding smoking and alcohol consumption. However, at present it can't be decided, if the risk-load within this group of applicants is even higher than among the non-applying workmen. Such a selection would be intended. Overweight is the main risk-factor among applicants for medical rehabilitation. It is present far more often than generally within the general population and even within the working class. Male workers with repeated courses of medical rehabilitation exhibit a significant lower risk-load than applicants for a first rehabilitative procedure. A causal relation might be suggested, but at present other explanations regarding the observed relationship have to be considered. A long-term Follow-up study is necessary.

Adult↗
PubMed1991

Effect of 3,4-methylenedioxymethamphetamine on [3H]paroxetine binding in the frontal cortex and blood platelets of rats.

The effects of single or repeated administration of the racemic mixture of 3,4-methylenedioxymethamphetamine (MDMA; 20 mg/kg, s.c.) on the number (Bmax) of serotonin (5-HT) uptake sites as determined by [3H]paroxetine binding and the concentration of 5-HT and its major metabolite, 5-hydroxyindoleacetic acid (5-HIAA), were measured in the frontal cortex and blood platelets of rats 1 and 7 days following its administration. A single injection of MDMA significantly (P less than 0.05) decreased the number of [3H]paroxetine binding sites as well as the concentrations of 5-HT and 5-HIAA in the frontal cortex but not in platelets 7 days following administration. Repeated injections of MDMA (twice daily for 4 days) significantly (P less than 0.05) decreased the number of 5-HT uptake sites and the concentration of 5-HT and 5-HIAA in the frontal cortex but not in platelets 7 days following administration. Pretreatment with the 5-HT2/5-HT1C antagonist, ketanserin, inhibited the MDMA-induced decrease in 5-HT and 5-HIAA concentrations and the number of [3H]paroxetine binding sites in the frontal cortex 7 days following a single administration. These data are suggestive that blood platelets are less sensitive than brain tissue to the 5-HT-depleting effects of MDMA. The ability of ketanserin pretreatment to block MDMA-induced decreases in [3H]paroxetine binding sites in the frontal cortex is suggestive that 5-HT2/5-HT1C receptors may be involved in the neurotoxic effects of MDMA.

3,4-Methylenedioxyamphetamine↗