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A Cohen

Publications and source records attributed to A Cohen.

At least 127 records · Page 7Linked to original sources
PubMed2000

Central diabetes insipidus in children and young adults.

BACKGROUND: Central diabetes insipidus is rare in children and young adults, and up to 50 percent of cases are idiopathic. The clinical presentation and the long-term course of this disorder are largely undefined. METHODS: We studied all 79 patients with central diabetes insipidus who were seen at four pediatric endocrinology units between 1970 and 1996. There were 37 male and 42 female patients whose median age at diagnosis was 7.0 years (range, 0.1 to 24.8). All patients underwent magnetic resonance imaging (MRI) and periodic studies of anterior pituitary function. The median duration of follow-up was 7.6 years (range, 1.6 to 26.2). RESULTS: The causes of the central diabetes insipidus were Langerhans-cell histiocytosis in 12 patients, an intracranial tumor in 18 patients, a skull fracture in 2 patients, and autoimmune polyendocrinopathy in 1 patient; 5 patients had familial disease. The cause was considered to be idiopathic in 41 patients (52 percent). In 74 patients (94 percent) the posterior pituitary was not hyperintense on the first MRI scan obtained, and 29 patients (37 percent) had thickening of the pituitary stalk. Eighteen patients had changes in the thickness of the pituitary stalk over time, ranging from normalization (six patients) or a decrease in thickness (one patient) to further thickening (seven patients) or thickening of a previously normal stalk (four patients). Anterior pituitary hormone deficiencies, primarily growth hormone deficiency, were documented in 48 patients (61 percent) a median of 0.6 year (range, 0.1 to 18.0) after the onset of central diabetes insipidus. CONCLUSIONS: Most children and young adults with acquired central diabetes insipidus have abnormal findings on MRI scans of the head, which may change over time, and at least half have anterior pituitary hormone deficiencies during follow-up.

Adolescent↗
PubMed2000

Impact of tissues heterogeneities on monitor units calculation and ICRU dose point: analysis of 30 cases of prostate cancer treated with 18-MV photons after three-dimensional planning.

PURPOSE: Analysis of dose specification of tissue heterogeneities. METHODS AND MATERIALS: Three-dimensional dose distribution analyses of 30 patients with localized prostate cancer were reviewed with and without tissue heterogeneity correction. The number of monitor units for each portal entrance (more than 300 different fields) was calculated and the impact of targeting and number of portal entrances was also integrated. RESULTS: The presence of gas in the rectum induces an overdosage of 0.6%, pubic bone induces an underdosage of -1.5%, and femoral heads are responsible for 6% underdosage. For the treatment as a whole, the underdosage is correlated with targeting techniques and weighting of each portal entrance (range, -0.5% to -3.2%). CONCLUSION: Dose calculation must take into account tissue heterogeneities and more precise guidelines for dose prescription are mandatory for further intercomparison.

Algorithms↗
PubMed2000

T cell immunity to copolymer 1 confers neuroprotection on the damaged optic nerve: possible therapy for optic neuropathies.

We recently reported that the posttraumatic spread of degeneration in the damaged optic nerve can be attenuated by the adoptive transfer of autoimmune T cells specific to myelin basic protein. However, it would be desirable to obtain immune neuroprotection free of any possible autoimmune disease. In an attempt to obtain disease-free immune neuroprotection, we used the synthetic four-amino acid polymer copolymer 1 (Cop-1), which is known not to be encephalitogenic despite its cross-reactivity with myelin basic protein. We show here that active immunization with Cop-1 administered in adjuvant, as well as adoptive transfer of T cells reactive to Cop-1, can inhibit the progression of secondary degeneration after crush injury of the rat optic nerve. These results have implications for the treatment of optic neuropathies.

Animals↗
PubMed2000

Mitochondrial basis for immune deficiency. Evidence from purine nucleoside phosphorylase-deficient mice.

We generated purine nucleoside phosphorylase (PNP)-deficient mice to gain insight into the mechanism of immune deficiency disease associated with PNP deficiency in humans. Similar to the human disease, PNP deficiency in mice causes an immunodeficiency that affects T lymphocytes more severely than B lymphocytes. PNP knockout mice exhibit impaired thymocyte differentiation, reduced mitogenic and allogeneic responses, and decreased numbers of maturing thymocytes and peripheral T cells. T lymphocytes of PNP-deficient mice exhibit increased apoptosis in vivo and higher sensitivity to gamma irradiation in vitro. We propose that the immune deficiency in PNP deficiency is a result of inhibition of mitochondrial DNA repair due to the accumulation of dGTP in the mitochondria. The end result is increased sensitivity of T cells to spontaneous mitochondrial DNA damage, leading to T cell depletion by apoptosis.

Animals↗
PubMed2000

The incidence of lymphoma in first-degree relatives of patients with Hodgkin disease and non-Hodgkin lymphoma: results and limitations of a registry-linked study.

BACKGROUND: The precise incidence of familial Hodgkin disease (HD) and non-Hodgkin lymphoma (NHL) in first-degree relatives is unknown. Through record linkage using two population-based sources, the authors estimated the risk of HD and NHL in family members of lymphoma probands. METHODS: The authors identified 8,037 first-degree relatives of 2,606 lymphoma cases (28.5% HD, 71.5% NHL) treated between 1970 and 1993 in 3 hospitals in Israel via the family file of the Population Registry. The authors linked this file with the Israel Cancer Registry, then calculated the standardized incidence ratio (SIR) by dividing the observed number of cases with the expected, adjusting for age, gender, calendar year, and continent of origin. RESULTS: The family file yielded incomplete ascertainment of relatives (for 771 probands, no relatives were identified). Twenty cases of lymphoma--6 HD and 14 NHL--were identified among relatives of lymphoma patients. The SIR for HD was 1.15 (95% confidence interval [CI]: 0.42-2.51) and for NHL 1.71 (95% CI: 0.93-2.87), considering the entire population of first-degree relatives. SIRs among siblings of lymphoma probands were 3.12 (95% CI: 1.01-7.29) for HD, 2.16 (95% CI: 0.45-6.31) for NHL, and 2.68 (95% CI: 1.15-5.27) for all lymphomas. There were 4 HD/HD, 1 NHL/NHL, and 3 NHL/HD sibling pairs. For HD/HD and NHL/NHL sibling pairs, the interval between lymphoma occurrence in proband and sibling was 1-4 years, whereas for HD/NHL pairs this ranged from 16 to 21 years. CONCLUSIONS: The risk of lymphoma among siblings of lymphoma probands was over 2.5-fold that of the general population and lower among other family members. The temporal proximity of HD/HD and NHL/NHL sibling pairs argues for environmental as well as genetic etiology. This method was hampered by incomplete data.

Adolescent↗
PubMed2000

Functional and quality-of-life outcomes in patients with rectal cancer after combined modality therapy, intraoperative radiation therapy, and sphincter preservation.

PURPOSE: Locally advanced primary and recurrent rectal cancers treated with external beam radiation therapy, intraoperative radiation therapy, and chemotherapy represent a complex group of patients in the setting of extensive pelvic surgery and sphincter preservation. We sought to define functional outcome and quality of life in this subset of patients. METHODS: We retrospectively reviewed our experience with locally advanced primary and recurrent rectal cancer patients who underwent intraoperative radiation therapy with either low anterior resection (n = 12) or coloanal anastomosis (n = 6) between 1991 and 1998. Current functional outcome and quality of life were evaluated by a detailed questionnaire. RESULTS: Median time from operation to assessment was 24 (range, 6-93) months. Using a standardized Sphincter Function Scale, incorporating the number of bowel movements per day and degree of incontinence, patients were graded as poor, fair, good, or excellent function. Of all patients, 56 percent reported unfavorable (poor or fair) function. Of the subset of patients with coloanal anastomosis or very low low anterior resection, 88 percent had unfavorable function as compared with 30 percent with standard low anterior resection. (P = 0.02; Fisher's exact probability test). A quality-of-life satisfaction score based on social, professional, and recreational restrictions demonstrated 56 percent of patients to be dissatisfied with their bowel function. CONCLUSIONS: The majority of patients with advanced rectal cancers who require external beam radiation therapy, extensive pelvic surgery, and intraoperative radiation therapy report unfavorable functional and quality-of-life outcomes after sphincter preservation. In this setting patients being considered for coloanal anastomosis or very low anterior resection may be better served by permanent diversion.

Adult↗
PubMed2000

Intensive care sedation: a review of current British practice.

OBJECTIVE: Sedation is central to the management of intensive care patients. Many different techniques have been tried, all have potential side effects, and some have been associated with serious adverse effects. The aim of this work is to establish current sedation practice in British ICUs; the use of neuromuscular blocking drugs and the indications for their use, the use of sedation policies and scoring systems, the influence of cost on drug choice, and the use of propofol for sedation in paediatric patients. DESIGN: A postal survey sent to all units identified in the Directory of Emergency Services. RESULTS: Two hundred and fifty-five replies were received from 323 questionnaires (79% response rate). The replies show that alfentanil, morphine, midazolam, and propofol are the most widely used drugs for sedation, and that changes occur in sedation policy with the time a patient spends in intensive care. Atracurium is the most widely used neuromuscular blocking drug, but the number of patients who receive therapeutic paralysis is relatively small and the indications for its use in different units is consistent. Propofol is used by many ICUs for the sedation of children despite reports linking its use to mortality in children and the advice of the regulatory authorities. CONCLUSIONS: Drugs used for the sedation of patients in intensive care have changed since previous surveys. The sedation policy of most units relies on the combination of small numbers of drugs. Sedation policies now seem to concentrate on achieving a lightly sedated co-operative patient.

Adult↗
PubMed2000

Compartment syndrome following isolated ankle fracture.

We report two cases of compartment syndrome following isolated ankle fractures. Both required decompression of all the compartments following early clinical diagnosis and measurements of the intra-compartmental pressures.

Adult↗
PubMed2000

Simultaneous bilateral femoral fractures: systemic complications in 14 cases.

We have retrospectively reviewed 14 patients with bilateral femoral shaft fractures who attended our institution between January 1993 and March 1999. The mean age of the patients was 38 years (19-75) and the median injury severity score (ISS) was 16 (interquartile range 10-20). Thirteen patients were treated with intramedullary nailing and 1 with plating and nailing within 24 h of admission to hospital. The mean resuscitation requirements were 10.6 (6-16) litres of colloid and crystalloid and 8.6 (4-30) units of blood. The mean intensive care unit/high dependency unit (ICU/HDU) stay was 4 days (1-14) and the mean hospital stay was 36.3 days (3-210). There were 6 cases of adult respiratory distress syndrome (ARDS), 1 compartment syndrome, 1 case of osteomyelitis, 1 above-knee amputation and 2 deaths (14.2%). The mean time to union was 24.5 weeks (12-37). Comparison to patients with unilateral injuries revealed a higher ISS, resuscitation requirements, ARDS, hospital stay and mortality.

Adult↗
PubMed2000

Laparoscopic cholecystectomy for acute cholecystitis: can the need for conversion and the probability of complications be predicted? A prospective study.

BACKGROUND: Laparoscopic cholecystectomy (LC) in acute cholecystitis is associated with a relatively high rate of conversion to an open procedure as well as a high rate of complications. The aim of this study was to analyze prospectively whether the need to convert and the probability of complications is predictable. METHODS: A total of 215 patients undergoing LC for acute cholecystitis were studied prospectively by analyzing the data accumulated in the process of investigation and treatment. Factors associated with conversion and complications were assessed to determine their predictive power. RESULTS: Conversion was indicated in 44 patients (20.5%), and complications occurred in 36 patients (17%). Male gender and age >60 years were associated with conversion, but these factors had no sensitivity and no positive predictive value. The same factors, together with a disease duration of >96 h, a nonpalpable gallbladder, a white blood count (WBC) of >18,000/cc(3), and advanced cholecystitis, predicted conversion with a sensitivity of 74%, a specificity of 86%, a positive predictive value of approximately 40%, and a negative predictive value of 96%. However, these data became available only when LC was underway. Male gender and a temperature of >38 degrees C were associated with complications, but these factors had no sensitivity and no positive predictive value. Progression along the stages of admission and therapy did not add predictive factors or improve the predictive characteristics. Male gender, abdominal scar, bilirubin >1 mg%, advanced cholecystitis, and conversion to open cholecystectomy were associated with infectious complications. Their sensitivity and positive predictive value remained 0 despite progression along the stages of admission and therapy. CONCLUSION: Although certain preoperative factors are associated with the need to convert a LC for acute cholecystitis, they have limited predictive power. Factors with higher predictive power are obtained only during LC. The need to convert can only be established during an attempt at LC. Preoperative and operative factors associated with total and infectious complications have no predictive power.

Adolescent↗
PubMed2000

Labor after previous cesarean: influence of prior indication and parity.

OBJECTIVE: To determine whether the risk of cesarean for women who had trials of labor after one prior cesarean differs from that of nulliparas overall and by indications for those cesareans. METHODS: We reviewed medical records of women who had trials of labor after cesareans between July 1984 and June 1996, and of nulliparas who delivered between December 1994 and August 1995. Cesarean rates for women with prior cesareans were compared with the rates for nulliparas overall and by prior cesarean indication (breech, failure to progress, nonreassuring fetal testing, or other). Lengths of labor for women who had repeat cesareans for failure to progress in index pregnancies were compared by prior cesarean indication. RESULTS: The cesarean rate was 28.7% (634 of 2207) for the prior cesarean group and 13.5% (219 of 1617) for nulliparas (P =.001), and varied according to the prior cesarean indication (13.9%, 37.3%, 25. 4%, and 24.8% for breech, failure to progress, nonreassuring fetal testing, and other, respectively). Mean durations of labor in the index pregnancies for women who had cesareans for failure to progress were 13.9, 11.5, 13.4, and 15.1 hours for breech, failure to progress, nonreassuring fetal testing, and other, respectively. CONCLUSION: Overall rates of cesareans were higher for women with one prior cesarean than for nulliparas. Rates of cesareans after trials of labor were related to the prior cesarean indications. Rates were highest for women whose prior cesareans were for failure to progress and lowest for women whose prior cesareans were for breech. The latter group had a rate that was essentially identical to that of nulliparas. Among women with cesareans for failure to progress in index pregnancies, lengths of labor were shorter for those whose prior cesareans were for failure to progress than for those whose prior cesareans were for other indications, suggesting that physicians may intervene earlier in these cases.

Female↗
PubMed2000

Whole-Body FDG-PET in Patients with Recurrent Colorectal Carcinoma. A Comparative Study with CT.

Purpose: To assess the clinical accuracy of whole-body 2-[F-18]-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) in the diagnosis of recurrent colorectal carcinoma in comparison to conventional computed tomography (CT).Materials and methods: Forty patients with suspected recurrent colorectal carcinoma based on either progressive serial carcinoemrbyonic antigen (CEA) serum elevation or positive/equivocal CT findings underwent whole-body FDG-PET. PET results were compared with those of CT and correlated to the final histopathological and clinical findings.Results: A final diagnosis was obtained at 93 sites in 35 patients by histology and in 5 patients by clinical follow up of at least 6 months. Of the 93 sites, 53 were determined to be malignant and 40 benign. FDG-PET evaluated on a 5-point scale (0-4) showed a positive and negative predictive value in the range of 96-98% and 83-93% respectively as the threshold for positivity was moved from 0 through 3. By comparison, CT, also evaluated on a 5-point scale showed a positive and negative predictive value in the range of 75-88% and 67-71% respectively. The area under the fitted receiver operating characteristic curve for PET: A(PET) = 0.96 +/- 0.02 was significantly greater (P < 0.001) than that observed for CT: A(CT) = 0.77 +/- 0.06. The distribution of maximum standardized uptake value (SUVmax) showed that all negative lesions have SUVmax below 5.0 whereas 75% of positive lesions were above 5.0 pointing to the fact that disease positivity is more likely in lesions with high SUV values.Conclusion: The results of this study confirm that whole-body FDG-PET is more accurate than conventional CT in the staging of patients with suspected recurrent colorectal carcinoma.

Journal Article↗