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Biomedical subjects

C Cox

Publications and source records attributed to C Cox.

At least 307 records · Page 17Linked to original sources
PubMed1993

On the mechanism of a 60-Hz electric field induced growth reduction of mammalian cells in vitro.

Data on 60-Hz electric field (EF) induced reduction in growth rate of plant roots have strongly supported the hypothesis that the effect is related to an EF-induced transmembrane potential (Vim). An investigation was undertaken to determine if this hypothesis is also applicable to 60-Hz EF-induced reductions in growth rate of mammalian cells in vitro. Human lymphoblastic (RPMI 1788) and human carcinoma (HeLa) cells were selected for study, the former having a relatively small diameter (11.2 microns), and the latter having a relatively large diameter (15.4 microns). The 60-Hz EFs ranged from 430-1200 V/m in the culture medium. The growth rate of RPMI 1788 cells after 4-days was depressed by about 42% at a 60-Hz EF of 1000-1200 V/m with a response threshold occurring at 950 V/m; the Vim at the response threshold was 8 mV. There was no 60-Hz EF-induced effect on HeLa cell growth rate of a Vim of 8 mV (60-Hz EF = 700 V/m); a statistically significant effect was achieved at Vim of 11 mV (950 V/m). The data support the hypothesis that above a threshold 60-Hz EF, Vim acts as the initial signal leading to growth rate reductions.

Cell Division↗
PubMed1993

All-trans retinoic acid plus low doses of cytarabine for the treatment of "poor-risk" acute myeloid leukemias.

Thirteen refractory/resistant AML patients no suitable for additional aggressive chemotherapy, were treated with a combination including all-trans retinoic acid (45 mg/m2 sine die) and low doses of Ara-C (20 mg/m2 subcutaneously, twice in a day, days 1-10, every 28 days). Ten patients were evaluable; 8 of them achieved a complete remission, two patients with an important tumor burden, failed to achieve a response. One complete remission patient relapsed after 7 months but is still receiving the same therapy and is now in partial remission. We believe this combination effective as inducer of complete remission in those AML patients which cannot tolerate additional heavy treatments. The role of tumor burden in affecting response to therapy remains to be still evaluated.

Aged↗
PubMed1993

Ultrasonographically guided subclavian vein catheterization in critical care obstetrics and gynecologic oncology.

Invasive hemodynamic monitoring has become an integral part of intensive care management. Whereas the pulmonary artery catheter is the mainstay for determination of the hemodynamic profile and differentiation between cardiogenic and noncardiogenic forms of pulmonary edema, immediate central venous access in itself is of importance in rapid volume replacement in cases complicated by severe hypovolemia. Central venous catheters are also the preferred route of administration of total parenteral nutrition to patients with cancer. We present our experience with real-time ultrasonographic guidance during subclavian vein catheterization in critical care obstetrics and gynecologic oncology.

Catheterization, Central Venous↗
PubMed1993

The anatomy of missed breast cancers.

Missed breast cancer continues to account for the highest percentage of medical malpractice cases in the United States. A retrospective, computer-aided study was performed to investigate the mechanisms of missed breast carcinomas, missed either by mammography or by clinical exam. In a consecutive series of 509 breast cancers found in patients registered at a University Comprehensive Breast Cancer Clinic, no tumour that was 5 mm or less in maximal diameter was clinically palpable. This subgroup consisted of seven in situ and 32 invasive carcinomas. The incidence of palpable tumours in 5 mm increments increased so that when a tumour was between 11 and 15 mm in size, 48% of the lesions were palpable, and with tumours greater than 20 mm in size, 84% were palpable. There was a good correlation between size of the tumour as judged by mammography and the eventual size determined by histologic examination. Smaller breast cancers were detected by mammography than by physical examination. In a separate analysis of 553 consecutive cases of breast cancer examined by mammography, there were 50 (9%) cases in which the cancer was not read from the mammogram. In retrospect, 10 of these mammograms were abnormal for a misinterpretation rate of 1.8%. Cancers associated with false negative mammograms occurred more often in younger women and in dense breast parenchyma than cancers detected by mammography. Cancers missed by mammography were smaller than palpable cancers detected by mammography, more often had negative nodes and presented with a lower stage of disease. Breast augmentation implants were associated more frequently with missed breast cancers, with 5/8 clinically detected breast carcinomas being undetected by mammography. An asymmetric mass was more often associated with cancers missed by mammography, accounting for the sole sign of malignancy in 3% of all cancers, but was the source of 14% of false negative exams. Architectural distortion, ill-defined or well circumscribed masses or calcifications as mammographic signs of malignancy were not associated with an increased frequency of missed cancers. Three 'interval' breast cancers occurred in this series and are included in the false negative mammograms. It is concluded that the threshold of clinically detected breast cancers is 6 mm and experienced clinicians do not detect the majority of breast cancers until the lesions are greater than 16 mm. Mammography has a defined misinterpretation and false negative rate. Likewise, asymmetric mammographic densities that are greater than 16 mm and are not palpable may be followed, since most breast cancers are palpable in this range.

Adult↗
PubMed1993

The gastroileoileal pouch: an alternative continent urinary reservoir for patients with short bowel, acidosis and/or extensive pelvic radiation.

We report on 6 patients who underwent a new type of continent urinary diversion: the gastroileoileal reservoir. These are a select group of patients who presented with the short bowel syndrome, acidosis, borderline diarrhea and/or severe pelvic radiation, which precluded the use of terminal ileum and the ileocecal segment. Considering these factors, and based on the different functional properties of the stomach as well as the need for a large reservoir, a segment of stomach and proximal ileum was used to construct the reservoir. Four patients have been followed for at least 6 months, with the longest followup being 12 months. Temporary dysphagia requiring hydrogen blockers developed in 1 patient. Results indicate excellent function of the continent urinary system, lack of metabolic complications, absent diarrhea and excellent patient tolerance. This procedure could be a useful alternative in some difficult clinical situations when continent urinary diversion is desirable.

Acidosis↗
PubMed1993

Hispanic culture and family care of Alzheimer's patients.

Caring for Alzheimer's patients places tremendous burdens and strain on families. This study examined the ways cultural values and norms influence the experiences of Hispanic caregivers. The results revealed relationships between attitudes toward caregiving and a sense of burden and depression among the caregivers, with depression being related to stronger adherence to norms of filial support. Factors associated with increased burden include lack of time for oneself, dependency needs of the patient, and belief that one could be doing a better job as caregiver. Problems common to other groups of caregivers--feelings of anger, relationship and financial strain, and isolation--were not apparent. Although relatives provide affective support, the burden of instrumental assistance rests on the primary caregiver. These findings, as well as a reluctance to discuss problems outside of the family, call for active social work interventions.

Alzheimer Disease↗
PubMed1993

Autonomic cardiovascular state after severe brain injury and brain death in children.

OBJECTIVE: To study and compare the autonomic cardiovascular state of children after severe brain injury and brain death. DESIGN: Prospective clinical study. SETTING: Pediatric ICU. PATIENTS: Pediatric patients suffering severe brain injury caused by trauma, anoxia, or hemorrhage. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: We analyzed cardiorespiratory parameters, heart rate power spectra, plasma catecholamine concentrations, and the response to the cold pressor test in nine brain-dead patients and compared the results with the test findings of 11 patients with severe brain injury. Low-frequency total heart rate power (p < .03), peak amplitude (p < .02), and plasma catecholamine concentrations (p < .001) were different with no overlap of values between groups. Cold pressor testing in patients with severe brain injury showed changes in respiratory rate and low-frequency heart rate power that were +/- 20% to 100% from baseline values; however, there were no measurable changes in brain-dead patients. CONCLUSIONS: Our results support the concept of a damaged sympathetic cardiovascular system in severe brain injury and complete interruption of the autonomic cardiovascular pathways in brain death. Since determination of brain death may be difficult, our findings have implications for corroborating brain death using autonomic cardiovascular testing.

Brain Death↗
PubMed1993

Inflicted versus accidental head injury in critically injured children.

OBJECTIVES: To assess the frequency of inflicted head injury in critically injured children; the severity of neurologic injury; the neurologic outcome; and the historical, socioeconomic, physical, and radiologic factors associated with inflicted head injury. DESIGN: Prospective clinical study. SETTING: Multidisciplinary pediatric intensive care unit (ICU). PATIENTS: Consecutive cases (n = 40) of severe head injury admitted to a pediatric ICU. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Fourteen (35%) of 40 cases of head injury were due to inflicted head injury. Eleven (79%) of 14 inflicted head injury cases were due to child abuse and three (21%) were due to neglect. The severity of neurologic injury, as measured by the admission Glasgow Coma Scale, was worse in cases of inflicted head injury (7.1 +/- 0.7 [SE] [inflicted] vs. 9.9 +/- 0.8 [accidental]; p = .04). Glasgow Outcome Scores were worse after inflicted head injury (2 +/- 1 inflicted] vs. 4 +/- 1 [accidental]; p = .004). In victims of child abuse, we found the combination of any two of the following three factors was associated with inflicted head injury: an inconsistent history/physical examination; retinal hemorrhages; or parental risk factors (alcohol or drug abuse, previous social service intervention within the family, or a past history of child abuse or neglect). CONCLUSIONS: This study confirms that severity of neurologic injury and neurologic outcome in cases of inflicted head injury are worse than in any other type of childhood head injury. We believe that a combination of any two of the above three risk factors may prove to be a reliable marker of inflicted head injury in children admitted to a pediatric ICU and will lead to an early and definitive diagnosis.

Accidents↗
PubMed1993

Validation of a measure of physical illness burden at autopsy: the Cumulative Illness Rating Scale.

OBJECTIVE: To further validate an objective measure of physical illness burden, the Cumulative Illness Rating Scale (CIRS). DESIGN: Survey with correlation of CIRS ratings made from physician interviews and review of medical records with post-mortem ratings made independently at tissue autopsy. SUBJECTS: Victims of completed suicide investigated by both psychological and tissue autopsy (n = 72). RESULTS: CIRS ratings made by examination of tissue at autopsy were highly predictive of analogous ratings based on historical data, accounting for 75% of the variance in CIRS scores. Taking autopsy findings as the gold standard of objective health assessment, historical ratings tend to underestimate physical illness at high levels of tissue pathology and to overestimate burden at lower levels. CONCLUSIONS: The CIRS score, when derived from all available sources of medical information, is a valid objective measure of physical illness burden and has broad applicability to research in geriatrics.

Adult↗
PubMed1993

Depressive symptoms, medical illness, and functional status in depressed psychiatric inpatients.

OBJECTIVE: There is evidence that both psychiatric (especially affective) and medical illnesses contribute to physical disability. However, the differential contributions of specific psychiatric disorders and of medical pathology to functional status in psychiatric populations have not been studied. The authors therefore examined the contributions of depressive symptoms and medical illness to functional disability in depressed inpatients. METHOD: This prospective investigation included 109 psychiatric inpatients with DSM-III-R major depression. Regression techniques were used to examine the contribution of demographic variables (age, sex, education), depressive symptom severity (Hamilton Rating Scale for Depression score), psychiatric function (Global Assessment of Functioning Scale score), organ system pathology (Cumulative Illness Rating Scale score), and medical disability (Karnofsky Performance Status Scale score) to overall functional status (Instrumental Activities of Daily Living and Physical Self-Maintenance scores). These relationships were also examined in older and younger subgroups. RESULTS: Greater age, female sex, and illness factors all contributed to poorer functional status. Of the illness factors, psychiatric pathology contributed more to low functional status than did medical illness. The predictive power came specifically from the functionally based measures of psychiatric and medical illness; a quantitative measure of symptoms (Hamilton depression scale) or organ pathology (Cumulative Illness Rating Scale) did not significantly predict overall functional status. CONCLUSIONS: Clinicians and researchers should recognize that symptomatic and functional assessments tap related but different domains and that both psychiatric and medical illnesses contribute to overall disability.

Activities of Daily Living↗
PubMed1993

Combined serum amylase and lipase determinations for diagnosis of suspected acute pancreatitis.

Serum amylase and lipase measurements are often used to diagnose acute pancreatitis. This study addresses the question of whether it is advantageous to order serum amylase and lipase tests simultaneously. We evaluated performance of the two tests separately and in combination through a retrospective study of patients for whom both amylase and lipase determinations were ordered. Initial analysis of test performance was conducted with a uniformly applied criterion based on determination of optimal sensitivity-specificity pairs. Individual tests and combinations of tests, including the "AND" and "OR" rules and discriminant functions, were examined. Only the discriminant approach demonstrated better performance than the lipase test alone. This finding was subsequently confirmed by logistic regression analysis. We conclude that ordering both tests simultaneously can be advantageous in diagnosing acute pancreatitis when a bivariate approach is used; however, this must be weighed against the difficulties associated with clinical implementation of such approaches.

Acute Disease↗
PubMed1993

Mrs Cleary's pain relief.

This case illustrates some common problems faced in general practice--the effects of personality and family dynamics on symptom reporting, the balance between over-investigation and under-investigation, and the dilemma of when to refuse to comply with patient requests for medication. Dealing with these is the art of good medicine.

Dextropropoxyphene↗
PubMed1993

The medical legal implications of following mammographic breast masses.

Delay in breast cancer diagnosis continues to account for the highest percentage of medical malpractice cases in the United States. A retrospective, computer-aided study was undertaken to investigate a number of parameters used in making medical-legal decisions in missed breast cancer cases. Over a 5-year period, 435 women with invasive breast cancers were registered at the Comprehensive University Breast Cancer Center. A close correlation between mammographic and final histologic size was verified (R = 0.74). In 5-mm increments, starting with a 1.0-mm tumor, there was an increasing percentage of positive nodes identified with increasing size of the tumor. Major percentage increases in frequency of positive nodes were noted at tumor sizes of 11 and 21 mm. This corresponded to an increasing number of recurrences and a decreasing 5-year disease-free survival (DFS) between consecutive 5-mm increments, although the differences were not significant. A multivariate regression analysis confirmed that the most important predictor of DFS was lymph node status (p = 0.0046) and not tumor size. After adjusting for lymph node status, tumor size was not significant. It is concluded that a period of observation, in which a breast cancer may increase in size is not substandard care since tumor size, after accounting for lymph node status is not significant at predicting DFS.

Breast↗
PubMed1992

The catecholamine response to multisystem trauma.

We studied the catecholamine response in two groups of patients with multisystem injuries according to the presence (group 1, N = 124) or absence (group 2, N = 82) of head injury. Markers of injury severity included the injury Severity Score, the Glasgow Coma Scale, the need for intubation, admission hypotension, the amount of blood products and fluid expanders administered during the first 24 hours, and patient outcome. In group 1, higher norepinephrine levels always and epinephrine concentrations usually were associated with worsening indexes of injury severity. The best correlations were between the Injury Severity Score and the Glasgow Coma Scale and norepinephrine concentrations. In group 2, despite elevated catecholamine levels, such associations were seldom present. Thus, circulating catecholamine levels, especially norepinephrine levels, significantly correlated with the severity of injury in patients who had suffered multisystem injury, but only if the injury included the brain.

Adolescent↗
PubMed1992

Foot currents and ankle SARs induced by dielectric heaters.

Data are presented on ankle-specific SARs and foot currents as a function of strengths of radio-frequency electromagnetic fields encountered by operators of dielectric heaters. The determination of foot currents was based on near-field exposures in which reactive coupling dominates, and which can result in substantial SARs in exposed workers. The operators were located less than one wavelength from--usually within one meter of--the dielectric heaters, which generated fields at frequencies from 6.5 to 65 MHz. At distances normally assumed by workers, maximal strengths of electric fields ranged from 10(4) to 2.4 x 10(6) V2/m2; maximal strengths of magnetic fields ranged from 5.0 x 10(-3) to 33.3 A2/m2. Currents through both feet to ground were measured while operators stood where they normally worked. Maximal currents ranged from 3 to 617 mA, rms. Nearly 27 percent of the dielectric heaters induced foot currents that exceeded the 200-mA limit that has been proposed for a new ANSI C95.1 standard. Twenty percent of the heaters induced foot currents that exceeded 350 mA. SARs in ankles were calculated from foot currents, and they approximated 5 W/kg at 100 mA, 29 W/kg at 250 mA, and 57 W/kg at 350 mA. The maximal SAR in the ankle was approximately 176 W/kg at 617 mA.

Ankle↗
PubMed1992

Comparative lethality of methanol, ethanol and mixtures in female rats.

The lethalities of pure methanol and pure ethanol were compared to two mixtures of ethanol/methanol with the following percentages (95/5% and 65/35% v/v). This study was conducted to simulate situations of human exposure to denaturated alcohol (by 5% methanol) or adulterated alcohol (by 35% methanol). Four groups of female adult virgin albino rats were treated with the four mixtures. A fifth group was used as a vehicle control. Graded oral doses were given to eight animals per dose. Lethality over 24 h was used as an end-point. The LD50 was calculated for each of the four treatments on a molar basis. A dose-response function for each mixture was plotted of percentage lethality vs. mmol kg-1 equivalent to the given ml kg-1 dose. Results showed a significantly different LD50 estimates (P less than 0.03) for the four mixtures. The order of lethal toxicity was as follows: 95/5% methanol/ethanol, pure methanol, pure ethanol then 65/35% methanol/ethanol. Slope comparisons indicated two pairs: 65/35% ethanol/methanol and pure ethanol yielding a steep slope, and 95/5% ethanol/methanol and pure methanol yielding a shallow slope. These data indicated that the acute lethality of ethanol/methanol mixtures is a complex unpredictable function. This toxicity presumably depends in a complicated way on the differences in the effective molecular weights of the two alcohols in each of the mixtures.

Animals↗