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K Cohen

Publications and source records attributed to K Cohen.

At least 19 recordsLinked to original sources
PubMed2005

Silencing p21(Waf1/Cip1/Sdi1) expression increases gene transduction efficiency in primitive human hematopoietic cells.

Adult hematopoietic and other tissue stem cells have highly constrained cell cycling that limits their susceptibility to standard gene therapy vectors, which depend upon chromosomal integration. Using cytokine cocktails to increase transduction efficiency often compromises subsequent stem cell function in vivo. We previously showed that p21(Waf1/Cip1/Sdi1) (p21) mediates stem cell quiescence in vivo and decreasing its expression ex vivo leads to an expansion of stem cell pool in vivo. Here, we report that application of p21 specific siRNA increased the gene transduction efficiency in hematopoietic stem cells while preserving cell multipotentiality. Both types of siRNA, synthesized siRNA and transcribed shRNA, reduced p21 expression in target cells by 85-98%. The effect of RNAi in these cells was transient and the level of p21 mRNA returned to base line 14-28 days after siRNA treatment. This brief interval of reduction, however, was sufficient to increase transduction efficiency to two- to four-fold in cell cultures, and followed by a seven- to eight-fold increase in mice. The RNAi treated, lentivector-transduced CD34+ cells retained multipotentiality as assessed in vitro by colony formation assay and in vivo by NOD/SCID mouse transplantation assay. Reduction of p21 resulted in an increased chromosomal integration of lentivector into target cellular DNA. Taken together, both synthesized and transcribed siRNA knocked down p21 expression in human CD34+ hematopoietic stem/progenitor cells. Silencing p21 expression increased gene transduction efficiency and vector integration while retaining stem cell multipotentiality. Thus, RNAi targeting of p21 is a useful strategy to increase stem cell gene transfer efficiency. Decreasing p21 expression transiently while increasing gene-transfer vector integration may ultimately facilitate clinical applications of gene therapy.

Adult↗
PubMed2000

Validation of a high-performance liquid chromatography method for the assay of and determination of related organic impurities in nevirapine drug substance.

Nevirapine (Viramune), a dipyridiodiazepinone, is a potent and highly specific nonnucleoside inhibitor of HIV-1 reverse transcriptase. This paper describes the validation of a specific, sensitive, and stability-indicating high-performance liquid chromatography method for the assay and determination of related organic impurities in nevirapine drug substance. This method uses a Supelcosil LC-ABZ column, a mobile phase of 20:80 (v/v) acetonitrile-25mM NH4H2PO4 (pH 5.0), and ultraviolet detection at a wavelength of 220 nm. This method was validated for specificity, linearity, accuracy, repeatability, detection limit, quantitation limit, stability of analyte solutions, robustness, and intermediate precision. Nevirapine is completely separated from all impurities. The method is shown to be linear with coefficients of determination r2 greater than 0.999. Average accuracy is 100.4% with a relative standard deviation of 0.7% for the assay. Accuracy ranges from 100.1 to 102.6% for related organic impurities. Repeatability is good, with relative standard deviations not more than 1.4%. The detection limit and the quantitation limit are determined to be 0.001 and 0.003%, respectively. Relative response factors of known organic impurities are determined, permitting the use of nevirapine at the 0.1% level as an external standard for the quantitation of these impurities. Analyte solutions are shown to be stable for at least 2 days at ambient temperature. The method is validated as robust, and intermediate precision is high. A system suitability test is developed and validated, and requirements are set.

Chromatography, High Pressure Liquid↗
PubMed1998

Native American medicine.

This article summarizes common principles, practices, and ethics of Native American healing, the traditional medicine of North America. Native American healing, spirituality, culture, and, in modern times, political, social, and economic concerns are closely intertwined. Intuition and spiritual awareness are a healer's most essential diagnostic tools. Therapeutic methods include prayer, music, ritual purification, herbalism, massage, ceremony, and personal innovations of individual healers. A community of friends, family, and helpers often participate in the healing intervention and help to alleviate the alienation caused by disease. A healthy patient has a healthy relationship with his or her community and, ultimately, with the greater community of nature known as "All Relations." The goal of Native American healing is to find wholeness, balance, harmony, beauty, and meaning. "Healing," making whole, is as important as curing disease; at times they are identical.

Complementary Therapies↗
PubMed1997

The Memorial Delirium Assessment Scale.

We conducted two studies with medically hospitalized cancer and acquired immunodeficiency syndrome (AIDS) patients to assess the reliability and validity of a new measure of delirium severity, the Memorial Delirium Assessment Scale (MDAS). The first study used multiple raters who jointly administered the MDAS to 33 patients, 17 of whom met DSM III-R/DSM IV criteria for delirium, 8 met diagnostic criteria for another cognitive impairment disorder (for example, dementia), and 8 had non-cognitive psychiatric disorders (for example, adjustment disorder). Results indicate high levels of inter-rater reliability for the MDAS (0.92) and the individual MDAS items (ranging from 0.64 to 0.99), as well as high levels of internal consistency (coefficient alpha = 0.91). Mean MDAS ratings differed significantly between delirious patients and the comparison sample of patients with other cognitive impairment disorders or no cognitive impairment (P < 0.0002). The second study compared MDAS ratings of 51 medically hospitalized delirious patients with cancer and AIDS made by one clinician to ratings on several other measures of delirium (Delirium Rating Scale, clinician's ratings of delirium severely) and cognitive functioning (Mini-Mental State Examination) made by a second clinician. Results demonstrated a high correlation between MDAS scores and ratings on the Delirium Rating Scale (r = 0.88, p < 0.0001), the Mini-Mental State Examination (r = -0.91, P < 0.0001), and clinician's global ratings of delirium severity (r = 0.89, P < 0.0001). Thus, our findings indicate that the MDAS is a brief, reliable tool for assessing delirium severity among medically ill populations that can be reliably scored by multiple raters. The MDAS is highly correlated with existing measures of delirium and cognitive impairment, yet offers several advantages over these instruments for repeated assessments which are often necessary in clinical research.

Adult↗
PubMed1996

Highly purified CD34-positive cells reconstitute hematopoiesis.

PURPOSE: The objective of this study was to characterize CD34+ cell grafts, obtained using a novel technique, from children undergoing autologous bone marrow transplantation (BMT) for cancer therapy. In particular, we wanted to determine if the CD34+ marrow cell grafts generated hematopoietic reconstitution, since a positive result would motivate further development and use of this methodology. PATIENTS AND METHODS: This pilot feasibility clinical trial involved 13 patients < or = 25 years of age with advanced solid tumors, including seven children with neuroblastoma. Harvested bone marrow underwent immunomagnetic CD34+ selection. RESULTS: In three of 13 enrolled patients, low purities of the CD34+ preparations disqualified the use of the CD34+ marrow grafts. Ten patients received myeloablative chemotherapy with etoposide, carboplatin, and cyclophosphamide, then were transplanted with CD34+ marrow grafts. In the 10 patients transplanted with CD34(+)-selected cells, the CD34+ cell purity (nucleated RBCs excluded) in the cell graft preparation was 91% total cell recovery from the starting light-density cells 2.2%, CD34+ cell recovery 38%, colony-forming unit-granulocyte-macrophage (CFU-GM) recovery 23%, and estimated tumor-cell depletion 2.6 logs (medians). The CD34+ marrow grafts administered to these patients contained a median of 2.3 x 10(6) nucleated cells, 1.4 x 10(6) CD34+ cells, and 1.3 x 10(4) CFU-GM per kilogram patient weight. Most patients experienced only the toxicities previously observed with this myeloblative chemotherapy regimen, although two unusual toxicities were observed. All 10 patients transplanted with CD34+ cell grafts engrafted. CONCLUSION: The CD34+ purified grafts were enriched in stem/progenitor cells, with five of these 10 preparations containing > or = 94% CD34+ cells. Engraftment with CD34(+)-purified cell grafts as pure as 99% confirms that autologous CD34+ cells, alone, are sufficient to provide hematopoietic rescue for myeloablated patients. The best purification results were obtained on small marrow harvests from patients with neuroblastoma. The engraftment of highly purified CD34+ cells obtained by this technology and the antitumor effect of the transplant, by which two of 10 poor prognosis patients remain clinically free of tumor, have stimulated further clinical trials.

Adolescent↗
PubMed1995

Primary cutaneous neuroendocrine tumors. Diagnostic use of cytogenetic and MIC2 analysis.

Merkel cell carcinoma (MCC) is a primary cutaneous neoplasm most commonly involving older adults. The cell of origin is thought to be the Merkel cell, a cutaneous neurosecretory cell. However, other neuroectodermal tumors may present in the skin and may be difficult to distinguish from MCC, including peripheral neuroectodermal tumors (PNET) and metastatic small cell carcinoma. We examined a primary cutaneous tumor of an 18-year-old which was strongly positive for cytokeratin (CK), neuron-specific enolase (NSE), and 12E7, an antibody to the protein determined by the MIC2 gene. Electron microscopy showed paranuclear aggregates of filaments and no cytoplasmic processes. These findings were considered to be consistent with MCC. Cytogenetic analysis demonstrated 46,XX,der(1)t(1;3;22)(1qter-->pa34::3q28-->q11::22q 12--> qter),der(3)t(1;3)(3pter-->q11::1p35-->pter), der(22)t(3;22)(22pter-->q11::?3q29-->qter). This was confirmed by chromosome painting using probes for chromosomes 1, 3, and 22. Peripheral neuroectodermal tumors (PNETs) show a characteristic translocation involving the same breakpoint on chromosome 22 that was present in this tumor. PNETs can also be CK and NSE positive. The MIC2 gene codes for a surface glycoprotein that has been shown to be very strongly and reliably expressed in PNETs, but not in other small round blue cell tumors and not in small cell carcinoma of the lung. However, MIC2 expression has not been studied in MCC. We investigated the use of MIC2 analysis in the distinction of MCC from PNET. Five additional MCCs were stained with the monoclonal 12E7 antibody, and one additional tumor showed the strong membranous positivity reported in PNETs. Our data suggest that MIC2 analysis may be useful in differentiating between MCC and PNET. However, cases will remain for which the distinction is elusive and cytogenetic analysis may be helpful.

Adolescent↗
PubMed1995

Identifying early dropouts from a rehabilitation program for psychiatric outpatients.

The attendance of 112 patients referred to an outpatient psychiatric rehabilitation program was retrospectively examined, and characteristics of dropouts were compared with those of patients who remained in treatment during the first eight weeks. Discriminant function analysis revealed that a combination of three variables correctly predicted 81 percent of the dropout group. The variables were a hostile, labile, or bizarre affect; a diagnosis of personality disorder; and impaired orientation. Patients with these characteristics require a thorough assessment of specific needs and deficits and ongoing evaluation of treatment approaches such as adaptations of psychosocial rehabilitation, dialectical behavior therapy, and assertive case management.

Adult↗
PubMed1994

Is alexithymia related to psychosomatic disorder and somatizing?

The purpose of this study was to examine the relationship among alexithymia (as measured by the Toronto Alexithymia Scale--TAS and the scored version of the Archetypal 9 Test--SAT9), the presence or absence of classical psychosomatic disease, and the experience and expression of physical signs and symptoms. Subjects included thirty-two physical signs and symptoms. Subjects included thirty-two in-patients on a psychosomatic medicine unit (somatizing group), thirty-one out-patients who presented to a psychology clinic (psychiatric group), and thirty-four dental patients (comparison group). All subjects completed the TAS, the SAT9, the Hypochondriasis scale of the Minnesota Multiphasic Personality Inventory (MMPI Hs), the Physical Malfunctioning subscale of the MMPI (MMPI Physm), the Somatic Complaints subscale of the MMPI (MMPI Somc), the Hypochondriasis and Denial scales of the Basic Personality Inventory (BPI Hs and BPI Dn), and a demographic questionnaire. Age was significantly correlated with some of the TAS subscales (p < 0.001). There was no significant differences in SAT9 or TAS scores among the three subject groups (SAT9 F(2, 87) = 1.88, p = 0.16; TAS F(2, 92) = 2.91, p = 0.06). MMPI Hs, MMPI Physm, MMPI Somc, BPI Hs could significantly predict TAS (R = 0.46, F(4, 89) = 6.06, p = 0.0002) but not SAT9 scores (R = 0.26, F(5, 84) = 1.54, p = 0.20). Neither TAS (F(2, 92) = 2.13, p = 0.12) or SAT9 (F(2, 87) = 0.095, p = 0.91) scores differed significantly between subjects grouped according to whether they had none, one, or two or more classical psychosomatic disorders.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Influence of ovarian cysts on the results of in vitro fertilization.

OBJECTIVE: To determine if ovarian cysts are associated with a particular basal endocrine profile and impair follicular growth. DESIGN: Retrospective study. SETTING: In Vitro Fertilization (IVF) Center. PATIENTS: Nine hundred fourteen stimulation cycles stimulated with a combination of luteinizing hormone-releasing hormone analogues (LH-RH-a) and human menopausal gonadotropins (hMG) in a long protocol in an IVF program. RESULTS: After 15 days of LH-RH-a therapy, ovarian cysts (> or = 20 mm) were observed in 8% of cases. These cysts were not related to a particular basal endocrine profile and did not impair follicular growth and IVF results. However, puncturing these cysts enhanced the quality of subsequent follicular growth. On the contrary, cysts appearing during hMG treatment (> or = 25 mm) were related with a lower LH:follicle-stimulating hormone ratio (0.79 +/- 0.52 versus 0.92 +/- 0.74 in absence of cyst) and to a lower ovarian response as assessed by the maximal estradiol level to the total number of hMG ampules ratio (51.6 +/- 36.5 versus 65.9 +/- 47.9 in absence of cyst). However, this difference had no influence on the pregnancy per stimulation rate (18% versus 16% in absence of cyst; not significant). CONCLUSIONS: Results show that the pathogens of ovarian cysts appearing during the blockage phase and during the stimulation phase are different. However, they do not impair the results of IVF, and thus it is not necessary to cancel the attempt in case of ovarian cyst.

Buserelin↗
PubMed1991

Newborns' head orientation toward trains of brief sounds.

Four experiments assessed the importance of stimulus number, repetition rate, and duration for newborns' head orientation toward brief sounds and related those parameters to the critical ones found for adults. Infants' responses to various trains of repeated 14-ms rattle sounds were compared with those to a 10-s rattle sound, known to elicit head orientation. Directional responses did not differ from the standard when rattle bursts were repeated at a rate of 20 per second for 1 s (experiment 1). Responding did differ from the standard and deteriorated to chance levels when either the number of moderately paced (6/s) stimulus bursts was decreased to six or fewer (experiments 2 and 3) or the duration of rapidly repeated (24/s) bursts was shortened to 500 ms (experiments 4A and 4B). These results suggest that newborns' head orientation depends, in part, upon the number of stimulus bursts and stimulus duration.

Adult↗
PubMed1989

Erythrocyte O2 transport and metabolism and effects of vitamin B6 therapy in type II diabetes mellitus.

The effects of vitamin B6 on erythrocyte metabolism, erythrocyte hemoglobin O2 affinity (P50), and nonenzymatic glycosylation were studied in 15 Caucasian men with type II (non-insulin-dependent) diabetes mellitus. A control group of 13 healthy Caucasian men was also evaluated. Before treatment, diabetic subjects had low mean cell hemoglobin concentration values and increases in both erythrocyte 2,3-diphosphoglycerate (2,3-DPG) levels and erythrocyte hexokinase activities. Although all three of these changes are associated with a decrease in hemoglobin O2 (Hb-O2) affinity, P50 values were normal in diabetic subjects. Moreover, P50 values normalized to pH 7.4 (P50(7.4] were inversely related to the level of glycosylated hemoglobin (HbA1c). Both erythrocyte 2,3-DPG and erythrocyte ATP were also inversely related to HbA1c. Vitamin B6 nutriture, as determined by erythrocyte aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities, was normal in all diabetic subjects before vitamin B6 therapy. Nonetheless, HbA1c levels decreased after 6 wk of treatment with 150 mg/day pyridoxine and increased again during placebo administration. These changes were not explained by changes in fasting blood glucose. Pyridoxine therapy also decreased P50(7.4) values and increased erythrocyte AST and ALT activities but had no effect on 2,3-DPG, ATP, or the activities of hexokinase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase. These observations suggest that 1) nonenzymatic glycosylation may play a role in regulating both erythrocyte metabolism and Hb-O2 affinity in diabetic subjects, and 2) vitamin B6 therapy may modify nonenzymatic glycosylation of hemoglobin in this population.

Animals↗
PubMed1989

A sectional denture as the optimal prosthesis.

A case is described where because of various local factors--anterior ridge loss, Class III skeletal relationship, survey lines, appearance, retention and support problems--a sectional prosthesis was found to be the optimal restoration.

Adult↗
PubMed1987

Age-related differences in lymphocyte adherence to myelinated tissue in multiple sclerosis.

Human peripheral blood lymphocytes were obtained from patients with MS and from healthy controls. Comparisons were made between the adherence of lymphocytes from donors of varying ages to myelin from donors of different age groups at the time of death. The adherence of control lymphocytes was maximum with lymphocytes from donors in their 30s. No obvious maximum for lymphocyte age was found for adherence of MS lymphocytes. However, MS adherence levels were significantly higher than control levels at most ages tested. Maximum adherence levels were observed for both MS and control cells with myelin from donors who were 20 to 45 years of age at the time of death. No significant difference between MS and control adherence to myelin from elderly donors was observed. Possible age-related changes in myelin and the relationship of maximum adherence to the peak age of onset of MS discussed.

Adolescent↗