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Biomedical subjects

S M Gordon

Publications and source records attributed to S M Gordon.

At least 91 records · Page 5Linked to original sources
PubMed1992

Changes in signs and symptoms following temporomandibular joint disc repositioning surgery.

Fifty-one subjects with documented intra-articular pathology refractory to non-surgical therapy underwent temporomandibular joint (TMJ) disc repositioning surgery. Following surgery, subjects were evaluated for 6 months to 6 years by clinical examinations and questionnaires at designated times, and by postsurgical joint imaging. Significant decreases were noted in pain (headache, TMJ pain, ear pain, and neck/shoulder pain), the incidence of joint sounds and locking, and the presence of dietary restrictions. However, 35% of the subjects continued to have residual TMJ pain, and a similar percentage continued to need periodic nonsteroidal anti-inflammatory drugs for analgesia. Some degree of dietary restriction remained in approximately 50% of the subjects, and joint sounds persisted in a similar percentage following surgery. Mean mouth opening was improved by 8 mm, although lateral movements were increased by less than 0.5 mm. Surgery did not decrease the occurrence of jaw deviation, and disc position was unchanged in 86% of the joints imaged at an average of 2 years following surgery. Although TMJ disc repositioning surgery significantly improved pain and dysfunction in TMJ surgery patients, the improvement in disc position was not maintained in most subjects following surgery.

Adolescent↗
PubMed1992

A cluster of severe postoperative bleeding following open heart surgery.

OBJECTIVE: To investigate a cluster of postoperative bleeding following open heart surgery. DESIGN: A cohort and case/control study. SETTING: Palo Alto Veterans Administration Medical Center, Palo Alto, California. PARTICIPANTS: Six (21.4%) of 28 patients undergoing open heart surgery who developed severe, nonsurgical, postoperative bleeding from July 1 through August 30, 1988 (outbreak period). All case-patients had chest tube drainage of greater than or equal to 1000 ml within 4 hours of surgery but did not have identifiable bleeding vessel(s) on exploration. RESULTS: Upon comparison of the pre-outbreak (January 1986 through June 1988) and the outbreak period, a significant increase was found in the incidence of postoperative nonsurgical bleeding (5/440 versus 6/28, p = .0006), but not of postoperative surgical bleeding (8/440 versus 0/28, p = 1.0). Of all patients undergoing open heart surgery during the outbreak period, case patients were found to be older (67.8 versus 60.6, p = .02) and to have received a larger volume of hetastarch (HES), a synthetic colloidal plasma-volume expander (mean = 19.4 ml/kg versus 14.1 ml/kg, p = .02). CONCLUSIONS: We conclude that the use of large volumes of HES during surgery in the elderly open heart surgery patient may increase the risk for severe, nonsurgical postoperative bleeding, probably caused by alterations of the coagulation system. As the incidence of open heart surgery increases among the elderly, surgeons and anesthesiologists should be alert to possible adverse reactions from exposures not associated with adverse reactions in younger patients.

Aged↗
PubMed1992

Culture isolation of Acanthamoeba species and leptomyxid amebas from patients with amebic meningoencephalitis, including two patients with AIDS.

Acanthamoeba species and leptomyxid organisms are free-living amebas that cause meningoencephalitis, primarily in immunocompromised patients. We report the isolation and culture of Acanthamoeba species and leptomyxid amebas from four patients with fatal amebic meningoencephalitis. Acanthamoeba species were cultured from brain abscess specimens from three immunocompromised patients (including two patients with AIDS). In the case of the fourth patient, who had no identifiable immunodeficiency, leptomyxid amebas were cultured from a specimen from a subcutaneous nodule and were identified in amebic granulomas in brain tissue by the indirect immunofluorescence test. Persons with advanced infection due to the human immunodeficiency virus may be at increased risk for amebic meningoencephalitis, but the diagnosis should be considered in the differential diagnosis of any immunocompromised patient with cerebral abscesses.

AIDS-Related Opportunistic Infections↗
PubMed1992

Pyrogenic reactions in patients receiving conventional, high-efficiency, or high-flux hemodialysis treatments with bicarbonate dialysate containing high concentrations of bacteria and endotoxin.

High-efficiency (HE) and high-flux (HF) hemodialysis are becoming increasingly popular methods for treating patients with chronic renal failure because they reduce the time required for dialysis treatment. HF and HE dialyzers require bicarbonate dialysate, often prepared from concentrates that can support bacterial growth with endotoxin production. There is a concern that endotoxins or bacteria may cross or interact at the membranes of these dialyzers, triggering the release of endogenous pyrogens (cytokines) by peripheral blood mononuclear cells to cause pyrogenic reactions (PR). To determine the incidence of PR and to examine the association between PR and levels of bacteria and endotoxin in dialysate, a cohort of patients receiving conventional, HE, or HF hemodialysis with bicarbonate dialysate and reprocessed dialyzers at three dialysis centers during a 12-month period was studied prospectively. All dialyzers underwent a test of membrane integrity before use. A total of 19 PR were identified among 18 patients in 26,877 hemodialysis treatments (0.7 PR/1,000 treatments). There was no significant difference in PR rates by treatment modality: conventional, 0.5 per 1,000 (7 PR/13,123 treatments) versus HE, 0.9 per 1,000 (9 PR/11,345) versus HF, 1.2 per 1,000 (3 PR/2,409) (P = 0.21; chi 2 test). Throughout the study period, bacterial counts for dialysate at each center significantly exceeded the Association for the Advancement of Medical Instrumentation's (AAMI) microbiologic standards for dialysate of less than 2,000 CFU/mL (mean, 19,000 CFU/mL), but water used in the reuse of dialyzers tested less than 200 CFU/mL.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

A prospective study of pyrogenic reactions in hemodialysis patients using bicarbonate dialysis fluids filtered to remove bacteria and endotoxin.

Pyrogenic reactions (PR) are a well-recognized complication of hemodialysis and have been associated with dialyzer reuse, high-flux dialysis, and bicarbonate dialysate. However, the roles of bacteria and endotoxin in dialysate for producing PR are not well defined. To determine the effect of removing most bacteria and endotoxin from the dialysate on the incidence of PR, a cohort of chronic hemodialysis patients receiving high-flux, high-efficiency, or conventional hemodialysis at three centers with bicarbonate dialysis fluids that had been filtered with a polysulfone high-flux hemodialyzer was prospectively studied. Unfiltered bicarbonate concentrate had median bacterial and endotoxin concentrations of 479,000 CFU/mL and 39,800 pg/mL, respectively. After filtration of the bicarbonate concentrate at the central proportioner, dialysate had a median 9.2 CFU/mL of bacteria and 17.8 pg/mL of endotoxin. Dialysate filtered at individual proportioning dialysis machines had a median 0.001 CFU/mL of bacteria and 0.19 pg/mL of endotoxin. Nine PR were identified among 303 patients after 28,007 hemodialysis treatments (0.3 PR/1,000 treatments). The rate of PR was similar for the three hemodialysis treatment modalities and for first-use compared with reused dialyzers. Although the PR rate in this study was lower (P = 0.046) than the PR rate of a previous study with unfiltered dialysis fluids (0.7 PR/1,000 treatments), it represents a difference of only 10 PR in over 28,000 treatments. It was concluded that filtration of hemodialysis fluids is efficacious in removing bacterial and endotoxin contamination and can result in a lower incidence of PR in patients receiving high-flux, high-efficiency, or conventional hemodialysis.

Adult↗
PubMed1992

Bacteriologic and endotoxin analysis of salvaged blood used in autologous transfusions during cardiac operations.

Autologous blood transfusion is a common method of reducing the need for heterologous blood transfusion during cardiac operations. Recently we investigated an outbreak of severe, nonsurgical postoperative bleeding among patients undergoing heart operations and receiving intraoperative transfusion of blood from a cell conservation device (Cell Saver System, Haemonetics Corp., Braintree, Mass.). As a result of this investigation, we conducted a prospective study to determine if bacterial or endotoxin contamination of the blood collected in the Cell Saver System and used for reinfusion during heart operations contributes to postoperative bleeding complications. Patients' blood samples were collected immediately before operation, at the end of cardiopulmonary bypass, 1 hour postoperatively, and from the Cell Saver System. All blood samples were cultured for bacteria, and all plasma samples were assayed for endotoxin. Preoperatively all patients having heart operations were without signs of infection, 33 of 37 blood cultures taken were negative, and none of the plasma samples had detectable endotoxin. After discontinuance of cardiopulmonary bypass but before delivery of blood from the Cell Saver System, bacteria and endotoxin were detected in 11 of 36 (30.6%) and five of 35 (14.3%) of the patients' blood samples, respectively. The blood aspirated from the open chest and collected by the Cell Saver System was culture positive in 30 of 31 (96.8%) samples, and seven of 29 (24.1%) contained endotoxin. One of 28 blood samples collected 1 hour postoperatively was culture positive, and five of 25 samples contained endotoxin. Of 61 total microorganisms isolated, 50 (82%) were coagulase-negative staphylococci, four (6.6%) aerobic diphtheroids, five (8.2%) anaerobic "diphtheroids" (Propionibacterium acnes), and two (3.2%) gram-negative bacilli. Plasma endotoxin concentrations ranged from 10 to 765 pg/ml. No signs of endotoxemia or unusual bleeding were observed intraoperatively or postoperatively in any of the 38 patients. Although blood collected in the Cell Saver System and used for reinfusion during heart operations often was contaminated with gram-positive bacterial commensals of the skin and low concentrations of endotoxin, no adverse effects were noted in the patients.

Bacteria↗
PubMed1991

A cluster of sternal wound infections requiring muscle flap repair: problems in epidemiologic investigation.

A cluster of sternal wound infections (SWI) requiring muscle flap closure occurred in a California hospital in 1988. Review of SWI rates by surgical team revealed that a single team (Team A) was associated with a cluster of SWI requiring muscle flap repair (MFR). Team A's rate of SWI requiring MFR was 2.27% in 441 heart operations. A case/control study was conducted to determine if the higher rate of SWI requiring MFR could be attributed to disproportionately large numbers of patients at high risk treated by Team A. Data on major risk factors for SWI collected for case and control groups included the following: age at operation, weight, body surface area, history of obesity, diabetes mellitus, or cigarette smoking, duration of cardiopulmonary bypass, use of internal mammary artery graft, number of coronary arteries bypassed, use of prostheses, operating room staffing, and emergent nature of operation. No statistically significant differences between Team A cases requiring MFR and control cases were observed for predisposing risk factors. Surgical technique remains a principal suspected risk factor for SWI requiring MFR in this cluster.

California↗
PubMed1991

Altered states of consciousness therapy. A missing component in alcohol and drug rehabilitation treatment.

Attaining altered states of consciousness is described as a basic human motive. The substance dependent population is distinguished from other populations because they pursue these states destructively by inappropriate use of alcohol and drugs. Despite a body of literature supporting the benefits of altered states of consciousness, alcohol and drug rehabilitation treatment programs fail to address this motive because of social disapproval, means-end confusion, and inadequate staff training. The authors maintain that Alcoholics Anonymous directs its members toward an altered state of consciousness called a spiritual awakening, which replaces the self-destructive pursuit of substance induced "highs." Failure to address patients' need for alternative methods of achieving altered states of consciousness is presented as part of the reason for relapse. An Altered States of Consciousness Therapy (ASCT) program is described that can be used to teach patients to consciously manipulate affect and cognition to achieve a new consciousness.

Alcoholics Anonymous↗
PubMed1991

Prevalence of resistance in patients receiving ganciclovir for serious cytomegalovirus infection.

Seventy-two AIDS patients treated with ganciclovir for cytomegalovirus (CMV) disease were prospectively monitored for the development of drug-resistant virus. No resistant strains were found in 31 patients before therapy or among seven culture-positive patients treated for less than or equal to 3 months. Of 13 culture-positive patients treated for greater than or equal to 3 months, 5 excreted virus resistant (ED50, greater than 12 microM, or ED90, greater than 30 microM) to ganciclovir. Thus, 38% of patients and receiving ganciclovir for greater than 3 months and excreting virus or, overall, 7.6% of the patients were excreting CMV resistant to the drug.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Identification of exposure markers in smokers' breath.

Volatile organic compounds present in the exhaled breath of 26 smokers and 43 non-smokers were evaluated in an effort to identify possible biochemical markers resulting from the exposure to cigarette smoke. The total ion current profiles obtained from gas chromatography-mass spectrometry (GC-MS), which contained about 230 GC-MS peaks, were first analyzed by using standard statistical procedures to select a subset of 22 peaks. The importance of the peaks was ranked using factor analysis, which further reduced the dimensionality of the data, and discriminant analysis served to develop classification functions. One peak, 2,5-dimethyl furan, had sufficient discriminatory power in the GC-MS profiles to allow almost complete differentiation (96% correct classification) between the smokers and non-smokers groups. In addition, several other compounds were able to separate the groups with a high level of accuracy.

Biomarkers↗
PubMed1990

Epidemic hypotension in a dialysis center caused by sodium azide.

The water used for dialysate (dialysis fluid) in hemodialysis centers is produced by water treatment systems (WTS), which require careful and frequent monitoring. On November 3, 1988, nine patients receiving hemodialysis treatments at a single dialysis center suddenly developed hypotension within 30 minutes of onset of dialysis. Eight patients exhibited symptoms and two experienced syncopal episodes; there were no deaths. The incidence of dialysis-associated hypotension occurring within 30 minutes after dialysis onset for these patients was significantly higher during outbreak treatments than during preoutbreak (September 1 through November 2, 1988) treatments, (9 of 9 vs. 0 of 238, P less than 0.00001, Fisher's t-test). Sodium azide, a potent hypotensive agent, was identified as the probable contaminant within the WTS of the dialysis center at the time of the outbreak because: 1) it was mixed with glycerine as the preservative solution of each of the four ultrafilters that were put on-line in the WTS without rinsing, 12 hours before the outbreak; and 2) high levels of total organic carbons were detected from dialysis water collected at point-of-use sites at the time of the outbreak, suggesting contamination of the WTS with the sodium azide-glycerine preservative solution. To prevent similar occurrences, we recommend that ultrafilters (and other components of the WTS) be rinsed free of potentially toxic chemicals prior to use. Dialysis center personnel need to be aware of the potential affects that each modification of disinfection of the WTS may have upon the product water used to prepare dialysate for patient treatments.

Aged↗
PubMed1990

Foodborne Snow Mountain agent gastroenteritis with secondary person-to-person spread in a retirement community.

A variety of small round-structured viruses are being recognized with increasing frequency as a cause of gastroenteritis in the community, but have rarely been reported to cause outbreaks in hospitals or extended-care facilities. From March 20 through April 15, 1988, an outbreak of gastroenteritis occurred in a retirement facility in the San Francisco Bay area. Illness was characterized by diarrhea, nausea, and vomiting; two residents died. Attack rates were 46% (155 of 336) in residents and 37% (28 of 75) in employees. During the initial outbreak period, illness among residents was associated with two shrimp meals served in the facility dining hall (odds ratio = 6.7). Person-to-person transmission probably occurred: The risk of becoming ill one or two days after a roommate became ill was significantly greater than that of becoming ill at other times during the outbreak (risk ratio = 6.5). Microbiologic examinations for bacterial and parasitic enteric pathogens were negative; however, 27-nm viral particles were detected by immune electron microscopy and by blocking enzyme immunoassay to Snow Mountain agent in stools obtained at the onset of illness from one of six ill residents. Seroconversion (greater than fourfold antibody rise) to Snow Mountain agent was detected in acute- and convalescent-phase serum specimens from five of six ill residents as measured by enzyme immunoassay, but not for Norwalk agent as measured by radioimmunoassay. This report of an outbreak of Snow Mountain agent gastroenteritis in an extended-care facility documents that these difficult-to-identify 27-nm viruses can cause outbreaks in inpatient settings.

Aged↗
PubMed1990

Risk factors for wound infections after total knee arthroplasty.

Wound infections are an infrequent but serious complication of total knee arthroplasty. Between January 1984 and November 1987, 20 of 243 (8.2%) patients at two affiliated hospitals developed surgical wound infections following 259 total knee arthroplasty procedures performed in clean-air operating rooms. Eighteen (90%) of the patients had deep infections; nine required removal of the prosthesis. A single surgeon (surgeon X) was associated with 18 of the procedures that had subsequent infection (risk ratio (RR) = 9.4, 95% confidence interval (CI) 2.2-39), and an investigation was carried out in an effort to explain the difference in infection rates between surgeon X and other surgeons. In a cohort study, stratified analyses identified a preoperative American Society of Anesthesiologists (ASA) physical status class greater than or equal to 3, surgeon X, and early postoperative use of a continuous passive motion device as risk factors associated with surgical wound infection following total knee arthroplasty procedures. Logistic regression analyses identified being a patient operated on by surgeon X with an ASA class greater than or equal to 3 as the only significant independent risk factor for total knee arthroplasty-associated surgical wound infections (RR = 9.3, 95% CI 2.8-31). The effect due to surgeon X could not be explained by receipt or timeliness of administration of antimicrobial prophylaxis, type of prosthesis inserted, duration of operation, postoperative use of continuous passive motion, or underlying etiology of joint disease. The authors conclude that surgical technique and patient's severity of illness were the primary determinants of surgical wound infection after total knee arthroplasty. This study demonstrates the complexity of epidemiologic investigation of surgical wound infections and the importance of considering patient severity of illness when interpreting surgeon-specific infection rates.

Cohort Studies↗
PubMed1990

Hemolysis associated with hydrogen peroxide at a pediatric dialysis center.

Patients receiving hemodialysis therapy risk exposure to disinfectants used to reduce bacterial burdens in hemodialysis equipment and to reprocess hemodialyzers. From April 29 through May 9, 1988, 3 patients undergoing hemodialysis treatments at a single center were exposed to dialysis fluid that was inadvertently contaminated with hydrogen peroxide (HP). All patients showed a significant decline in blood hemoglobin level and required packed red blood cell transfusions during the 11-day exposure to HP. Contamination of dialysis fluid may have been due to the inadequate rinsing of HP from the water treatment system (WTS) following its disinfection on April 27-28, 1988. The failure to check water at point-of-use stations with a sensitive enough test kit after the disinfection for HP permitted patient exposure to contaminated dialysis fluid. To prevent similar occurrences, we recommend that after each disinfection (or other modifications of the WTS), the WTS be adequately rinsed to remove potentially toxic chemicals. Dialysis center personnel need to be aware of the potential effects that each modification or disinfection of the WTS may have on the product water used.

Adolescent↗
PubMed1990

Role of the central nervous system in hemodynamic and sympathoadrenal responses to cocaine in rats.

These studies were undertaken to examine the contribution of central nervous system mechanisms to the cardiovascular and sympathoadrenal effects of cocaine. Changes in systolic and diastolic blood pressure, heart rate and plasma catecholamine concentrations were determined in response to cocaine injected i.a. or i.c.v. in conscious unrestrained rats. Systemically administered cocaine produced brisk, transient dose-related increases in systolic and diastolic pressure at doses of 0.05 to 5 mg/kg i.a. Plasma catecholamine concentrations increased in a dose-related manner, reaching peak levels at 5 to 10 min after i.a. cocaine injection. Only the higher doses of cocaine induced reflex vagal bradycardia that was blocked by atropine (0.4 mg/kg i.a.). Propranolol (1 mg/kg i.a.) prolonged the duration of cocaine-induced hypertension and bradycardia. Ganglionic blockade with chlorisondamine (7.5 mg/kg i.a.) antagonized completely the cardiovascular and sympathoadrenal effects of cocaine, indicating that intact ganglionic transmission is required for full expression of the autonomic responses. Antagonist drugs selective for the D-1 or D-2 dopamine receptors attenuated effects of cocaine on plasma catecholamine concentrations but not on cardiovascular parameters. Intracerebroventricular injection of cocaine (50-250 micrograms) increased systolic pressure and plasma catecholamine concentrations, providing direct evidence for an action of cocaine in the central nervous system. These results demonstrate that cocaine acts centrally to increase sympathetic outflow leading to hypertension and reflex bradycardia in conscious rats.

Animals↗
PubMed1989

Epidemic iatrogenic Acinetobacter spp. meningitis following administration of intrathecal methotrexate.

We report the first outbreak of Acinetobacter species meningitis in a group of children with acute leukaemia following the administration of intrathecal chemotherapy. Eight of twenty patients receiving methotrexate injections on a single day developed signs and symptoms of meningitis within 18 h of treatment, and cases were clustered by time of administration. A cohort study comparing case and non-case patients did not identify any specific host factor associated with meningitis. Acinetobacter calcoaceticus var anitratus was isolated from the cerebrospinal fluid (CSF) of five patients; three patients died. Our investigation determined that the methotrexate was extrinsically contaminated by reused needles, used for reconstitution and administration, which had been inadequately sterilized. Acinetobacter calcoaceticus var anitratus was isolated from an autoclaved needle and a vial of methotrexate used for chemotherapy; these and the clinical isolates had similar antibiograms. After introduction of single-use disposable needles no subsequent cases occurred.

Acinetobacter Infections↗
PubMed1989

Submarine atmospheres.

Nuclear submariners live and work in an atmosphere composed of approximately 80% naturally occurring nitrogen, 19% oxygen (manufactured aboard ship), and a complex mixture of inorganic and organic contaminants. The concentrations of contaminants exist as a balance between the rates of production from human and operational activities and the rate of removal by engineering systems. The biological effects of inorganic gases, particularly carbon dioxide, have been extensively studied. Investigators are now attempting to define the composition and concentration of volatile organic compounds that accumulate during 90-day submergences. Medical studies have not conclusively shown that crewmembers incur adverse health effects from continuous exposures to the sealed atmospheres of nuclear submarines.

Air Pollutants, Occupational↗