Efficiency of plasmid delivery and expression after lipid-mediated gene transfer to human cells in vitro

Cationic liposome-mediated gene transfer has become increasingly important in the development of experimental therapies for human diseases, such as melanoma, human immunodeficiency virus infection, cystic fibrosis and alpha-1 antitrypsin deficiency. However, very little is known about the mechanisms by which lipid-mediated gene transfer occurs. We studied the kinetics of plasmid delivery and expression by using this technique. Plasmid entry in the cystic fibrosis respiratory epithelial cell line 2CFSME0-1 as well as in two other cell lines (HeP 2g and HeLa) occurred in 95 to 100% of cells within 1 hr of the initiation of lipid-mediated gene transfer. In hepatic and respiratory cells, transcription of a construct containing the cystic fibrosis transmembrane conductance regulator was observed in more than 80% of the cell population; similarly high levels of plasmid utilization were obtained in studies of HLA-B7 expression in human melanoma cells. Studies directly relevant to current human trials of lipid-mediated gene transfer indicate that plasmid entry, transcription and translation are often surprisingly efficient, and may occur in nearly 100% of human cells in culture when sensitive methods for detection are used. Furthermore, conventional X-gal immunohistochemistry markedly underestimates transfection efficiency during transient gene expression. These studies point to a new mechanistic understanding of the features that limit expression by using cationic liposomes.

Mutations of the BRCA2 gene in ovarian carcinomas

Inherited mutations in the recently discovered BRCA2 gene are believed to be responsible for a significant fraction of early-onset hereditary breast cancers. Unlike BRCA1, however, which confers a high risk to both breast and ovarian cancer, the incidence of ovarian cancer appears to be much lower In BRCA2-linked families, causing uncertainty as to the relevance of BRCA2 to hereditary ovarian cancer. Numerous allelotype studies indicate that allelic deletions Including the BRCA2 locus on chromosome 13q are common in ovarian cancers in general, suggesting that somatic mutations of this gene may be involved in sporadic ovarian tumorigenesis. The purpose of this study was to test the hypothesis that germline or somatic mutations of BRCA2 are associated with hereditary and/or sporadic ovarian cancers, respectively. The entire 10.2-kb coding region of BRCA2 was screened for mutations in 130 consecutive ovarian tumors, the only selection criterion being a pathological diagnosis of epithelial ovarian carcinoma. Loss of heterozygosity at markers flanking BRCA2 was observed in 56% of the tumors. Four germline mutations and two somatic mutations were identified; two of the germline mutations are recurrent, having been previously described. Remarkably, the patients with germline mutations were late-onset cases with no medical or family histories suggestive of hereditary cancer. These data suggest that mutations of BRCA2 are rare in sporadic ovarian cancers, and that the proportion of ovarian cancers resulting from hereditary predisposition may be higher than previously suspected based on estimates derived from studies of highly penetrant genetic loci.

Tips and tricks: the hard way--ABCs of quadriplegia care

The following are things I have learned, routines my nurses have brought to me, or that we have developed together during 11-years existence with amyotropic lateral sclerosis (ALS) eight of which have been burdened by ALS induced quadriplegia and ventilator dependence. Items are listed, not in order of importance, which may vary from individual to individual, but alphabetically. Some are unique. Some commonplace. All are useful and many are of surprising value. Deviations from common understanding or practice are marked with an asterisk, and practices that can afford significant economies are double asterisked. This is written in an attempt to share with others in the profession lessons I have learned from personal experience--the hard way.

Resting energy expenditure of patients with gynecologic malignancies

OBJECTIVE

To evaluate resting energy expenditure compared to predicted energy expenditure in patients with cervical or ovarian carcinoma who require specialized nutritional support.

DESIGN

Women with biopsy-proven cervical or ovarian carcinoma referred to the Nutrition Support Service were studied. Resting energy expenditure was measured by indirect calorimetry and compared to predicted energy expenditure (PEE) as determined by the Harris-Benedict equation for females.

RESULTS

Sixty one patients were studied. Patients with ovarian cancer (n = 31) had a significantly higher measured resting energy expenditure (% PEE) than patients with cervical cancer (109 +/- 18% vs. 98 +/- 16%, p < 0.02, respectively). This difference in measured resting energy expenditure between groups could not be explained by differences in the extent of disease, nutritional status, body temperature, or nutrient intake between groups. A greater proportion of patients with ovarian cancer were hypermetabolic (> 110% of predicted) in comparison to patients with cervical cancer (55% vs. 13%, p < 0.01, respectively). Measured resting energy expenditure varied between 53% and 157% of predicted for the entire population.

CONCLUSION

Ovarian cancer patients are more hypermetabolic than cervical cancer patients. The Harris-Benedict equation for females is a unreliable estimate of caloric expenditure in patients with cervical or ovarian cancer receiving specialized nutritional support.

Review: DSM-IV and pain

The American Psychiatric Association recently published the fourth edition of its Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). Although earlier editions included pain-related diagnosis, inherent problems in their construction limited their applicability. This article discusses how DSM-IV deals with pain, with a specific focus on the new diagnostic category of Pain Disorder.

Expression and mutation analysis of the p53 gene in uterine papillary serous carcinoma

BACKGROUND

The status of p53 protein expression was determined by immunohistochemistry and correlated with genetic analysis and clinical outcome in patients with uterine papillary serous carcinoma (UPSC).

METHODS

Twenty-two patients with UPSC were identified and immunohistochemical staining of p53 protein was performed. Staining was analyzed by quantitating nuclear reactivity in 500 randomly counted cells per specimen. DNA analysis was performed on the tumors using single-strand conformation polymorphism (SSCP) analysis of exons 4-10 of the p53 gene, followed by DNA sequencing of all variants. Clinical data and patient status were ascertained from chart reviews.

RESULTS

Sixteen of the 22 (73%) tumors were scored as p53-overexpressing as determined by immunohistochemical analysis. Patients whose tumors overexpressed p53 had a statistically significant shorter survival than those whose tumors did not (P < 0.022). DNA analysis of the 22 tumors revealed five with mutations of the p53 gene. Only three of these mutations were observed in tumors that overexpressed p53.

CONCLUSIONS

A relatively large percentage of UPSC tumors exhibited high p53 immunoreactivity. Overexpression is correlated with poor prognosis. Positive immunohistochemistry for p53 protein in UPSC is not necessarily indicative of a genetic mutation.

Xeroderma pigmentosum variant: generation and characterization of fibroblastic cell lines transformed with SV40 large T antigen

Xeroderma pigmentosum variant (XPV) fibroblasts from the XP4BE strain (CRL1162) were transformed with the SV40 large T antigen with the purpose of generating immortalized cell lines that are defective in post-replication repair (PRR). Two transformation and selection protocols were used and at least two independent clones were obtained, which behaved in culture as immortal cell lines. Fingerprinting analyses were used to demonstrate their origin from XP4BE cells and to compare their genetic profiles. These cell lines were shown to be hypersensitive to killing by uv when compared to SV40-transformed fibroblasts derived from foreskins of normal neonates. One of the XPV transformed cell lines (CTag) was characterized further as a potential source of cell-free extracts with capability for catalyzing the T antigen-dependent in vitro replication of plasmid DNA carrying the SV40 origin of replication. In this assay system, CTag extracts were shown to be as active as those produced from HeLa cells. In vitro replication of uv-damaged plasmid DNA by protein extracts from PRR-defective (XPV) and PRR-proficient cells might allow the identification and characterization of protein factors that contribute to normal replication of uv-damaged DNA. Ultraviolet irradiation of plasmid DNA templates caused dose-dependent inhibition of in vitro replication by both HeLa and CTag extracts.

Sarcoidosis in a uterine leiomyoma

Sarcoidosis is a granulomatous condition of unknown etiology. Though the lung and lymph nodes are most commonly involved, other organs may also be affected. Involvement of the female reproductive system is very uncommon and usually has been found in the endometrium or myometrium. A case is described of a 43-year-old nulligravida who presented for evaluation of a dry cough and who was found to have a pelvic mass. Preoperative evaluation revealed the presence of pulmonary sarcoidosis. At the time of exploratory laparotomy, a large, pedunculated fibroid was resected along with an inflammatory cyst. Histopathologic examination revealed the presence of sarcoid lesions within the fibroid. This is the first report of such a finding, and the implications are discussed.

Primary care physicians and pain: education during residency

OBJECTIVE

This study examines whether family practice residents are receiving adequate training in the evaluation and treatment of pain during their residencies.

DESIGN

A survey of the training directors of all family practice residency programs in the United States (n = 390) was conducted by mail. Questions were included regarding the residency programs and training in and knowledge of common pain conditions and therapies.

PARTICIPANTS

Of all the training directors surveyed, 258 (66%) responded.

MAIN OUTCOME MEASURE

The relationship between adequate training in pain and the characteristics of the residency programs was examined.

RESULTS

Twenty-nine percent of the training directors who responded considered that their residents received adequate training in the recognition and treatment of pain. Adequate training correlated with rotation through pain services and the number of hours of lecture on pain provided. While the majority of program directors reported that their trainees were receiving training in many of the common pain syndromes and the use of analgesic medications, significantly fewer (p < 0.001) considered it to be adequate.

CONCLUSIONS

Family practice training directors do not believe their residents are receiving adequate training in pain. In light of previous studies indicating the importance of providing proper pain treatment, enhanced teaching on this subject during residency appears to be needed.

The problems of pain and its detection among geriatric nursing home residents

OBJECTIVE

To assess physicians' detection of pain among geriatric nursing home residents and to determine if there are factors that may interfere with their ability to do this.

DESIGN

Chart review and patient interview.

SETTING

Geriatric nursing home.

PARTICIPANTS

One hundred nursing home residents age 65 or older. Seventy-six were communicative.

MEASUREMENTS

Demographic information, diagnoses, and medication use were compared for several groups of residents to determine their effects on the detection of pain.

RESULTS

Sixty-six percent of the communicative residents were identified as having chronic pain. Treating physicians did not detect this problem in 34% of these residents. Those whose pain was not so identified were more likely to have a neurologic disorder other than dementia. When non-communicative residents were compared with those who were communicative, the physicians were found to have identified pain less frequently in the former cohort.

CONCLUSIONS

Chronic pain is a common problem among geriatric nursing home residents and is frequently undetected. Identification of this problem among communicative residents may be markedly improved by direct questioning about this problem at frequent intervals. New methods of assessing pain need to be created to assist in its detection among the non-communicative population.