Doxorubicin induced expression of P-glycoprotein in a canine osteosarcoma cell line

Canine and human osteosarcoma are very similar with respect to clinical presentation, radiological and histopathological features, metastatic rate and pattern and response to therapy. For these reasons, canine osteosarcoma is a useful intermediate model for the disease in humans. Overexpression of P-glycoprotein, the product of the MDR1 gene, is the most important predictor of an adverse clinical course in human patients with osteosarcoma. Exposure of canine osteosarcoma cells to doxorubicin resulted in overexpression of MDR1 mRNA and P-glycoprotein. Furthermore, these cells failed to accumulate doxorubicin intracellularly and were less sensitive to vincristine-induced cytotoxicity as compared to parental cells.

Identification and localization of extracellular Ca(2+)-sensing receptor in rat intestine

The extracellular calcium (Ca2+o)-sensing receptor (CaR) plays vital roles in Ca2+o homeostasis, but no data are available on its expression in small and large intestine. Polymerase chain reaction products amplified from reverse-transcribed duodenal RNA using CaR-specific primers showed > 99% homology with the rat kidney CaR. Northern analysis with a CaR-specific cRNA probe demonstrated 4.1- and 7.5-kb transcripts in all intestinal segments. Immunohistochemistry with CaR-specific antisera showed clear basal staining of epithelial cells of small intestinal villi and crypts and modest apical staining of the former, whereas there was both basal and apical staining of colonic crypt epithelial cells. In situ hybridization and immunohistochemistry also demonstrated CaR expression in Auerbach's myenteric plexus of small and large intestines and in the submucosa in the region of Meissner's plexus. Our results reveal CaR expression in several cell types of small and large intestine, in which it may modulate absorptive and/or secretomotor functions.

Plexosarcoma of the bladder

Plexosarcomas are rare soft tissue sarcomas, previously reported in association with gastrointestinal autonomic nerve (GAN) plexi. We report the first case arising from the autonomic nerve plexus of the bladder.

Squamous cell carcinoma originating from a cutaneous scar in a llama

A nonhealing wound associated with a laceration in a 12-year-old llama was evaluated. Initial attempts at closure were unsuccessful and biopsy revealed scar tissue. Subsequent biopsies, 18 mo later, revealed squamous cell carcinoma with regional metastasis. This report describes squamous cell carcinoma, secondary to a traumatic wound in a llama.

Skin appendage involvement in anal intraepithelial neoplasia

BACKGROUND

High-grade anal intraepithelial neoplasia (AIN III) may be premalignant. Surgical excision of large areas of anal epithelium carries significant morbidity. Ablation treatments may carry less morbidity; however, the depth of ablation is uncertain and failure to ablate dysplasia in hair shafts and other skin appendages may lead to early recurrence.

METHODS

This study assesses morphometric aspects of skin appendages in perianal skin and anal canal mucosa in tissues from 30 patients with AIN III. Both normal and dysplastic epithelium was assessed in each patient. The depth to which AIN III involved skin appendages was measured using computerized image analysis.

RESULTS

Both the perianal epidermis and anal canal mucosa affected by AIN III were significantly thicker than normal. Nineteen of 30 patients with AIN III had skin appendage involvement. Some 57 per cent of hair follicles (79 of 138), 16 per cent of sebaceous glands (11 of 69) and 25 per cent of sweat glands (24 of 96) observed beneath an abnormal epithelium had evidence of AIN. The median depth of AIN involvement of the hair follicle was 1.14 (range 0.44-1.67) mm, sebaceous glands 1.44 (range 0.96-1.90) mm, and sweat glands 0.94 (range 0.50-2.20) mm. These figures do not take into account tissue shrinkage due to histological processing.

CONCLUSION

AIN III involvement of epithelial appendages is a significant problem. For disease eradication, tissue destruction or removal to a depth of at least 2.2 mm below the adjacent basement membrane is required. Surgical excision of high-grade AIN remains the treatment of choice.

Amyloid-beta proteins activate Ca(2+)-permeable channels through calcium-sensing receptors

The amyloid-beta peptides (A beta) are produced in excess in Alzheimer's disease (AD) and may contribute to neuronal dysfunction and degeneration. This study provides strong evidence for a novel cellular target for the actions of A beta, the phospholipase C-coupled, extracellular Ca(2+)-sensing receptor (CaR). We demonstrate that A beta(s) produce a CaR-mediated activation of a Ca(2+)-permeable, nonselective cation channel (NCC), probably via elevation in cytosolic Ca2+ (Cai), in cultured hippocampal pyramidal neurons from normal rats and from wild type mice but not those from mice with targeted disruption of the CaR gene (CaR -/-). A beta(s) also activate NCC in CaR-transfected but not in nontransfected human embryonic kidney (HEK293) cells. Thus aggregates of A beta deposited on hippocampal neurons in AD could appropriately activate the CaR, stimulating Ca(2+)-permeable channels and causing sustained elevation of Cai with resultant neuronal dysfunction.

Tardive dyskinesia exacerbated after ingestion of phenylalanine by schizophrenic patients

Despite continued research, the influences that promote or exacerbate tardive dyskinesia (TD) symptoms remain incompletely understood. Recent findings (Gardos et al. 1992; Richardson et al. 1989) suggest that ingestion of the dietary constituent, phenylalanine, might exacerbate TD symptoms, but a double-blind, placebo-controlled challenge had not previously been conducted in schizophrenic patients. On two different mornings, in counterbalanced order, 18 male schizophrenic patients with TD were challenged with either 100 mg/kg phenylalanine or placebo. Effects on abnormal involuntary movements, recall memory, and plasma phenylalanine were measured 90 minutes post-challenge. The results supported the hypothesis in that involuntary movements increased to a statistically and clinically meaningful degree after the phenylalanine challenge, but not after placebo. No effects on memory were detected. Significant order effects characterized the plasma findings but not the behavioral data. Results indicate that a dietary constituent, the amino acid phenylalanine, can potentially exacerbate tardive dyskinesia symptoms in schizophrenic patients. The influence of phenylalanine and other ingested substances on clinical symptomatology warrants further investigation.

Knowledge and Attitudes of Certified Athletic Trainers in Pennsylvania Toward HIV/AIDS and Treating HIV-Positive Athletes

OBJECTIVE

As the number of people infected with the Human Immunodeficiency Virus (HIV) continues to increase so does the likelihood that athletic trainers will treat HIV-positive athletes. The purposes of this study were to determine how knowledgeable certified athletic trainers in Pennsylvania are about HIV/ AIDS and their attitudes toward treating the injuries of HIV- positive/AIDS athletes. Another purpose of this study was to determine what effect the athletic trainers' HIV/AIDS attitudes had on their HIV/AIDS knowledge level.

DESIGN AND SETTING

A questionnaire was mailed to 807 NATA-certified athletic trainers who resided in the state of Pennsylvania. A total of 410 (50.8%) athletic trainers participated in the study: 241 (58.8%) males and 169 (41.2%) females.

SUBJECTS

NATA-certified athletic trainers who resided in the state of Pennsylvania as of March 19, 1994.

MEASUREMENTS

A questionnaire was developed by the investigators after reviewing the appropriate literature and in consultation with a panel of experts that consisted of athletic trainers, physicians, and a health educator who specialized in HIV/AIDS education. The questionnaire consisted of three sections: demographic information, HIV/AIDS knowledge, and HIV/AIDS attitude. Returned questionnaires were analyzed via descriptive (frequencies, percentages, and means) and inferential statistics. Univariate analysis consisted of independent t tests to determine what effect the athletic trainers' HIV/AIDS attitudes had on their HIV/AIDS knowledge level.

RESULTS

NATA-certified athletic trainers in Pennsylvania are moderately knowledgeable about HIV/AIDS and have constructive attitudes in treating the athletic injuries of HIV-positive/ AIDS athletes. Their major concern, however, is fear of HIV transmission. It was further determined that differences in HIV/AIDS attitudes had no effect on HIV/ AIDS knowledge level.

CONCLUSIONS

The likelihood that athletic trainers will treat HIV-positive athletes is ever increasing. HIV/AIDS education and appropriate clinical precautions are paramount in protecting the clinician and athlete alike.

Agonists of the Ca(2+)-sensing receptor (CaR) activate nonselective cation channels in HEK293 cells stably transfected with the human CaR

Calcium (Ca2+) ions serve multiple roles both intra- and extracellularly. We recently cloned a cell surface, Cao(2+)-sensing receptor (CaR) that plays a central role in Cao2+ homeostasis by enabling direct regulation by Cao2+ of parathyroid hormone (PTH) secretion and the function of other tissues involved in mineral ion homeostasis. In parathyroid cells, the CaR activates phospholipase C, thereby raising the levels of inositol trisphosphate (IP3) and releasing Ca2+ from intracellular stores. High Cao2+ also activates Ca2+ influx into parathyroid cells through poorly defined mechanisms that may involve Ca(2+)-permeable, nonselective cation channels (NCC). We now show that human embryonic kidney (HEK293) cells also have NCC and, furthermore, that these channels are regulated by the CaR. We have utilized the cell-attached configuration of the patch clamp technique to characterize the properties of these channels as well as their regulation by various CaR agonists added to the external bath solution. The polycationic CaR agonist, neomycin (100 microM), as well as an elevated concentration of Cao2+ (3 mM), both of which activate the cloned CaR, significantly increased the probability of channel opening (Po) in HEK cells stably transfected with the CaR but not in nontransfected HEK cells which do not contain the receptor. Thus, the activation of the CaR enhances the activity of Ca(2+)-permeable NCC in these cells, which could contribute to the sustained increase in Cai2+ in parathyroid cells which is observed in response to elevated Cao2+. The CaR may also regulate the membrane functions of other CaR-expressing cells (e.g., those in the brain), at least in part, by modulating similar channels.

Effect of syringe size on bruising following subcutaneous heparin injection

BACKGROUND: Bruising and induration associated with subcutaneous heparin injection often result in sustained tenderness and severe ecchymosis at the injection site. Research-based practice guidelines for subcutaneous heparin administration are needed to reduce these adverse effects. OBJECTIVES: The purpose of this study was to investigate the effect of syringe size (1-mL vs 3-mL) on postinjection-site bruising and induration following the administration of subcutaneous heparin. METHODS: A convenience sample of 29 subjects receiving 5000 units of subcutaneous heparin at least twice a day was recruited from a large urban hospital. Subjects received their regularly scheduled subcutaneous heparin injections with a 3-mL or a 1-mL syringe in a randomized sequence using a standardized procedure. Injection sites were assessed for bruises and induration at 24, 48, and 72 hours after injection. RESULTS: The incidence of injection site bruising with 1- and 3-mL syringes was 79% and 69%, respectively. The use of a 3-mL vs 1-mL syringe resulted in significantly smaller bruises at 48 and 72 hours after injection. Induration at the injection site occurred in three patients. CONCLUSIONS: Findings suggest that 3-mL syringes are preferable to 1-mL syringes for heparin administration. The effect of other injection-related variables should be studied with the use of the 3-mL syringe, and tested on various populations.

Effect of syringe size on bruising following subcutaneous heparin injection

BACKGROUND

Bruising and induration associated with subcutaneous heparin injection often result in sustained tenderness and severe ecchymosis at the injection site. Research-based practice guidelines for subcutaneous heparin administration are needed to reduce these adverse effects.

OBJECTIVES

The purpose of this study was to investigate the effect of syringe size (1-mL vs 3-mL) on postinjection-site bruising and induration following the administration of subcutaneous heparin.

METHODS

A convenience sample of 29 subjects receiving 5000 units of subcutaneous heparin at least twice a day was recruited from a large urban hospital. Subjects received their regularly scheduled subcutaneous heparin injections with a 3-mL or a 1-mL syringe in a randomized sequence using a standardized procedure. Injection sites were assessed for bruises and induration at 24, 48, and 72 hours after injection.

RESULTS

The incidence of injection site bruising with 1- and 3-mL syringes was 79% and 69%, respectively. The use of a 3-mL vs 1-mL syringe resulted in significantly smaller bruises at 48 and 72 hours after injection. Induration at the injection site occurred in three patients.

CONCLUSIONS

Findings suggest that 3-mL syringes are preferable to 1-mL syringes for heparin administration. The effect of other injection-related variables should be studied with the use of the 3-mL syringe, and tested on various populations.

Escherichia coli tryptophanyl-tRNA synthetase mutants selected for tryptophan auxotrophy implicate the dimer interface in optimizing amino acid binding

Tryptophan auxotrophs of Escherichia coli in which mutations were mapped to the trpS locus (encoding tryptophanyl-tRNA synthetase) have been previously isolated. We have investigated the tryptophanyl-tRNA synthetase (TrpRS) purified from six auxotrophic strains for changes in amino acid activation and aminoacylation. Steady-state kinetic analyses show that these mutant TrpRS proteins have increases in the apparent KM for tryptophan, decreases in turnover number, or both, without significant changes in the apparent KM for ATP or tRNA(Trp). The crystal structure of a highly homologous tryptophanyl-tRNA synthetase from Bacillus stearothermophilus in a complex with the cognate aminoacyl adenylate allowed us to place the mutations in a structural context. The mutations in the enzymes are located in the KMSKS loop (M196I), in or near the active site (D112E, P129S, A133E) or far from the active site. The last three mutants (T60R, L91F, G329S) could not be predicted by examination of the protein structure as they line an interface between the C-terminal alpha-helix of one subunit and the Rossmann folds of both subunits, thus affecting a specific region of the dimer interface. These results support a role for dimerization in properly configuring the two active sites of the dimeric enzymes in the Trp/Tyr subclass of class I aminoacyl-tRNA synthetases in order to achieve optimal catalysis.

The effect of ambient temperature on the shoe-surface interface release coefficient

Previous studies of the shoe-surface interface correlated foot fixation with cleat length, configuration, and material composition as well as turf type and surface conditions. Our study examined the effect of temperature on the rotational torsion resistance of artificial turf football shoes. Five football shoe models, a flat-soled basketball-style turf shoe, a natural grass soccer-style shoe, and three multistudded turf shoes, were studied on dry Astro Turf at five temperatures (range, 52 degrees F to 110 degrees F). An assay device, a prosthetic foot mounted on a loaded stainless steel shaft, was used to determine the force necessary to release a shoe from the turf's surface. We used a torque wrench to apply a rotational force so that each shoe was pivoted counterclockwise through an arc of 60 degrees. Our results indicated that release coefficients differ within and among the shoe models at various turf temperatures. We also found that an increase in turf temperature, in combination with cleat characteristics, affects shoe-surface interface friction and potentially places the athlete's knee and ankle at risk of injury. Based on an established risk criterion, which correlated shoe-surface interface combinations in the laboratory with documented clinical occurrences, only the flat-soled basketball-style turf shoe could be designated "safe" or "probably safe" at all five temperatures.

Pharmacokinetics of pyropheophorbide-a-hexyl ether in the dog

BACKGROUND AND OBJECTIVES

Pyropheophorbide-a-hexyl ether (HPPH) is a new compound being investigated for use as a photosensitizer for photodynamic therapy; however, the pharmacokinetics are not known for any of the target species likely to be treated with this drug. The objective of this study was to determine the pharmacokinetic parameters of this drug prior to institution of a clinical trial in canine patients with various cancers.

STUDY DESIGN, MATERIALS AND METHODS

HPPH (0.3mg/kg i.v.) was administered to 12 dogs and blood samples were drawn at intervals for 24 hours and plasma HPPH concentrations were determined. Pharmacokinetic parameters were calculated for each dog.

RESULTS

No evidence of toxicity was noted in any dog. The mean half-life was calculated to be 26.98 +/- 2.35 hrs. The mean clearance was 5.061 +/- 0.214 ml/hr/kg. The mean volume of distribution of the central compartment was 0.069 +/- 0.003 L/kg, and the mean steady state volume of distribution was 4.47 +/- 0.25 L/kg.

CONCLUSION

The conclusion is that 0.3 mg/kg HPPH injected intravenously resulted in measurable plasma levels for 24 hrs, and resulted in no detectable adverse reactions.

Drugs, poverty, pregnancy, and foster care in Los Angeles, California, 1989 to 1991

To determine the characteristics and childbearing histories of women whose infants entered foster care in Los Angeles County, we examined the cases of 1,155 drug-using women whose infants were removed from them at birth and 236 non-drug-using women whose infants were also removed at birth by court order (July 1989 through March 1991). All of the women were indigent, and less than half had graduated from high school. The drug-using women frequently had criminal records, and more than a quarter were homeless. Many comparison women had mental health problems, and some (16.7%) were teenagers under court custody. Overall, 80% of all the children born to both groups of women were under court jurisdiction. Data obtained after study infants' births on 926 drug-using women observed for 18 months revealed that 22% had borne another infant who was placed in foster care; half of these infants had a positive drug immunoassay. Of the 185 non-drug-using women with 18-month follow-ups, 7.6% had borne another child who was in foster care. The magnitude of the repeated childbearing recorded among both groups of women in this study shows that preventive programs including family planning, mental health services, and drug prevention or rehabilitation programs have not reached this population.

Psychiatric consequences of radical curative surgery for gastric cancer

Radical resection of gastric cancer offers the best hope of cure, but carries the risk of significant psychological morbidity in addition to the well-documented physical complications. In the case presented, recognition of clinical depression after thoracoabdominal gastrectomy enabled successful psychological intervention.

Radical surgery for advanced and recurrent breast cancer

Locally advanced or recurrent breast cancer is commonly seen in breast clinics. One method of palliation for ulcerating tumours is a radical mastectomy with replacement of the chest wall defect with a myocutaneous flap. We report on our experience of this technique in the management of 35 women (21 advanced disease, 14 recurrent disease). The perioperative complications were minimal and there are some longterm survivors. 15 women are alive and well (range 20-96 months postoperatively, mean 55 months). This radical surgery, therefore, has a significant role in the management of selected women with breast cancer.

Determinants of birth weight in Vietnamese detainees in Hong Kong

Five hundred and fifty singleton pregnancies amongst Vietnamese Boat People delivering between January and December 1993 were studied post-natally. Multiple regression analysis showed no direct effect of ethnic origin on birth weight. When analyses were repeated on the two main ethnic subgroups we found that, amongst Anamese patients, both gestation at delivery and birth weight independently increased with longer duration of stay in Hong Kong. This relationship was not seen in Vietnamese patients of Chinese ethnic origin. Possible reasons for these different relationships are discussed.

Treatment of anal intraepithelial neoplasia

The natural history and malignant potential of anal intraepithelial neoplasia (AIN) remain uncertain, making management decisions about such lesions difficult. The management of 70 patients with AIN is described. The majority of lesions encountered were low grade (AIN I and II; 43 of 70) and required no treatment, but eight invasive anal cancers associated with high-grade AIN occurred over the 4-year study period. Three were a result of apparent progression of high-grade lesions; three more invasive lesions were found in areas of AIN III on histological examination. Surgical excision was used to treat 27 patients with AIN III. Treatment of extensive lesions involving the perianal and anal canal epithelium circumferentially in six patients involved excision of the whole of this epithelium and application of split skin grafts.