Human metabotropic glutamate receptor 2 couples to the MAP kinase cascade in chinese hamster ovary cells

We have examined the functional coupling of the human metabotropic glutamate receptor type 2 (mGluR2) with the regulation of the mitogen activated protein kinase (MAP kinase) signal transduction cascade. We demonstrated that L-glutamate stimulation of the human mGluR2 receptor transiently expressed in chinese hamster ovary (CHO) cells leads to a rapid increase in the activity of p42/p44 MAP kinase (also known as the extracellular signal regulated kinases, ERK1 and ERK2). Activation of p42/p44 MAP kinase has been demonstrated in a peptide phosphorylation assay and through the demonstration of a shift in electrophoretic mobility of p42 MAP kinase following activation. In both assay systems L-glutamate stimulation of MAP kinase was inhibited by pertussis toxin and by the MEK (MAP/ERK activating kinase) inhibitor PD 98059. We conclude that L-glutamate stimulation of the mGluR2 receptor in CHO cells mediated regulation of p42/p44 MAP kinase following the activation of pertussis toxin-sensitive G alpha(i) G-proteins via a distinct protein kinase signalling pathway that utilizes MEK.

Immunohistochemical localisation of mGluR7 protein in the rodent and human cerebellar cortex using subtype specific antibodies

Metabotropic glutamate receptors (mGluRs) are a heterogeneous family of G protein coupled receptors that are linked to multiple second messenger systems to regulate neuronal excitability and synaptic transmission. To characterise the protein expression of the two mGluR7 receptor splice variants in human and rat cerebellar cortex, antibodies specific to mGluR7 were generated. Antibodies were raised against a glutathione-S-transferase fusion protein containing amino acid residues located in the extracellular domain common to both the human and rat mGluR7 splice variants. These antibodies specifically detected human mGluR7a in mammalian cells transfected with this receptor. In agreement with mGluR7 in situ hybridisation studies, immunohistochemistry performed at the light microscope level revealed that mGluR7 protein expression occurred most prominently in a particular population of nerve cells common to both the human and rat, located within the cerebellar cortex of gray matter contained within transverse folia. Moreover, strong mGluR7-like immunoreactivity was seen in Purkinje cell body cytoplasm of the Purkinje cell layer. In the most superficial cerebellar cortical layer, the molecular layer, immunostaining was observed in Purkinje cell associated proximal and distal dendritic trees. No detectable labelling was evident in intrinsic deep cerebellar nuclei known to contain GABAergic terminals of projecting Purkinje cell axons. These data are suggestive of a post-synaptic location of mGluR7 in this central nervous system structure. In the rodent, additional non-Purkinje cells thought to represent inhibitory interneurones were labelled at all levels in the molecular layer. mGluR7-like immunoreactivity was not associated with glial cells.

Localization of mGluR4 protein in the rat cerebral cortex and hippocampus

The cellular distribution of the rat metabotropic glutamate receptor type 4 (mGluR4) was examined in the adult rat cerebral cortex and hippocampus. Antibodies were raised against amino acid residues located in the extracellular amino terminal domain that is common to both the mGluR4a and mGluR4b splice variants, and used for an immunohistochemical investigation. The affinity-purified antibodies on immunoblot analysis specifically detected mGluR4 protein in transfected mammalian cells, showing no cross-reactivity with other members of the mGluR family. At the light microscope level intense mGluR4-like immunoreactivity was detected in the CA2 region of Ammon's horn in the hippocampus. In the cerebral cortex numerous non-pyramidal cells were strongly immunolabelled.

Expression of a novel splice variant of human mGluR1 in the cerebellum

We have isolated clones of a novel splice variant of metabotropic glutamate receptor type 1 (mGluR1) from a human cerebellum cDNA library. Translation of this variant, mGluR1g would result in the addition of just one amino acid after the exon/intron boundary where the other splice variants diverge. RNA dot blot analysis using an mGluR1g-specific probe demonstrated expression in the cerebellum and also high levels in the kidney. Northern blotting using the same probe showed expression of a 4 kb transcript in the cerebellum. In situ hybridization studies in the cerebellum showed that mGluR1g mRNA is only expressed in granule cells, compared with mGluR1a/b mRNA which is also found in Purkinje cells and basket cells. Transcripts of the analogous splice variant are also present in rat brain mRNA.

Recursive partitioning analysis (RPA) of prognostic factors in three Radiation Therapy Oncology Group (RTOG) brain metastases trials

PURPOSE

Promising results from new approaches such as radiosurgery or stereotactic surgery of brain metastases have recently been reported. Are these results due to the therapy alone or can the results be attributed in part to patient selection? An analysis of tumor/patient characteristics and treatment variables in previous Radiation Therapy Oncology Group (RTOG) brain metastases studies was considered necessary to fully evaluate the benefit of these new interventions.

METHODS AND MATERIALS

The database included 1200 patients from three consecutive RTOG trials conducted between 1979 and 1993, which tested several different dose fractionation schemes and radiation sensitizers. Using recursive partitioning analysis (RPA), a statistical methodology which creates a regression tree according to prognostic significance, eighteen pretreatment characteristics and three treatment-related variables were analyzed.

RESULTS

According to the RPA tree the best survival (median: 7.1 months) was observed in patients < 65 years of age with a Karnofsky Performance Status (KPS) of at least 70, and a controlled primary tumor with the brain the only site of metastases. The worst survival (median: 2.3 months) was seen in patients with a KPS less than 70. All other patients had relatively minor differences in observed survival, with a median of 4.2 months.

CONCLUSIONS

Based on this analysis, we suggest the following three classes: Class 1: patients with KPS > or = 70, < 65 years of age with controlled primary and no extracranial metastases; Class 3: KPS < 70; Class 2- all others. Using these classes or stages, new treatment techniques can be tested on homogeneous patient groups.

The cementless anatomic medullary locking femoral component: an independent clinical and radiographic assessment

OBJECTIVE

To review the clinical performance of the anatomic medullary locking (AML) femoral stem in total hip arthroplasty.

DESIGN

A clinical and radiographic review.

SETTING

A tertiary lower limb joint replacement centre.

PATIENTS

Two hundred and twenty-one patients with noninflammatory gonarthrosis.

INTERVENTIONS

Two hundred and twenty-seven primary total hip arthroplasties with the noncemented AML component completed by two surgeons.

MAIN OUTCOME MEASURES

Independent review by two experienced reviewers of the postoperative Harris hip score, radiographs of component fixation, size and degree of diaphyseal fill.

RESULTS

Harris hip score was 84 (range from 43 to 98); component fixation showed bone ingrowth in 41%, stable fixation with fibrous ingrowth in 56% and unstable fixation in 3%; severe thigh pain in 4% of cases correlated with unstable fixation, and there was mild thigh pain in 20% of cases.

CONCLUSION

The AML femoral stem performs well in replacement arthroplasty compared with other noncemented stems.

A humanized system for pharmacologic control of gene expression

Gene therapy was originally conceived as a medical intervention to replace or correct defective genes in patients with inherited disorders. However, it may have much broader potential as an alternative delivery platform for protein therapeutics, such as cytokines, hormones, antibodies and novel engineered proteins. One key technical barrier to the widespread implementation of this form of therapy is the need for precise control over the level of protein production. A suitable system for pharmacologic control of therapeutic gene expression would permit precise titration of gene product dosage, intermittent or pulsatile treatment, and ready termination of therapy by withdrawal of the activating drug. We set out to design such a system with the following properties: (1) low baseline expression and high induction ratio; (2) positive control by an orally bioavailable small-molecule drug; (3) reduced potential for immune recognition through the exclusive use of human proteins; and (4) modularity to allow the independent optimization of each component using the tools of protein engineering. We report here the properties of this system and demonstrate its use to control circulating levels of human growth hormone in mice implanted with engineered human cells.

Synthesis and characterization of hydroxylated polychlorinated biphenyls (PCBs) identified in human serum

Hydroxylated polychlorinated biphenyls (PCBs) have been identified in wildlife and human samples. Most of these compounds are highly chlorinated (penta-hepatachloro) and contain a single meta- or para-hydroxyl group. Using the Cadogan coupling procedure, the following hydroxy-PCBs congeners were synthesized: 2,3,3',4',5-pentachloro-4-biphenylol, 2,3',4,4',5-pentachloro-3-biphenylol, 2',3,3',4',5-pentachloro-4-biphenylol, 2,2',3',4,4'-pentachloro-3-biphenylol, 2,2',3,3',4',5-pentachloro-4-biphenylol, 2,2',3',4,4',5-hexachloro-3-biphenylol, 2,2',3,4',5,5'-hexachloro-4-biphenylol, 2,2',3,3',4',5,5'-heptachloro-4-biphenylol, 2,2',3',4,4',5,5'-hepatachloro-3-biphenylol, 2,2',3,4',5,5',6-heptachloro-4-biphenylol. Many of these compounds have been detected as residues in human serum and current studies are investigating their activities as agonists and antagonists for several endocrine-mediated responses.

A study of the impact of leg ulcers on quality of life: financial, social, and psychologic implications

BACKGROUND

Leg ulcers affect probably 2.5 million persons in the United States, and their prevalence is likely to rise as the population ages. They cause considerable disability, and the cost of treating these chronic wounds is enormous.

OBJECTIVE

The purpose of this study was to assess the financial, social, and psychologic implications of leg ulcers.

METHODS

Data were collected by standardized personal interviews with 73 patients with chronic leg ulcers. The interview covered several domains that were selected to determine the impact of a leg ulcer on overall quality of life.

RESULTS

A significant number of patients had moderate to severe symptoms, principally pain, related to the leg ulcer. Eighty-one percent believed that their mobility was adversely affected by the ulcer; the dominant predictor of impaired mobility was swelling of the leg (p < 0.001). For younger, working patients, leg ulceration was correlated with time lost from work (p < 0.001), job loss (p < 0.01), and adverse effects on finances (p < 0.02). Fifty-eight percent of patients found caring for the ulcer burdensome. There was a strong correlation between time spent on ulcer care and feelings of anger and resentment. Sixty-eight percent of patients reported that the ulcer had a negative emotional impact on their lives, including feelings of fear, social isolation, anger, depression, and negative self-image.

CONCLUSION

Leg ulcers pose a substantial threat to a variety of dimensions of a patient's quality of life.

Posttranscriptional effector domains in the Rev proteins of feline immunodeficiency virus and equine infectious anemia virus

By systematically dissecting the Rev proteins of feline immunodeficiency virus (FIV) and equine infectious anemia virus (EIAV), we have identified within each a short peptide that is functionally interchangeable with the effector domains found in Rev-like proteins from other retroviruses. The active sequences from FIV and EIAV differ in several respects from other known effectors and may represent a distinct class of effector domain.

Helium ions versus iodine 125 brachytherapy in the management of uveal melanoma. A prospective, randomized, dynamically balanced trial

PURPOSE

Optimal radiation therapy for uveal melanoma is uncertain, and the relative efficacies of radioactive plaques and charged particles are unclear.

METHODS

The authors prospectively studied helium-ion irradiation and iodine 125 (125I) brachytherapy in a randomized, dynamically balanced trial. Of the 184 patients who met the eligibility criteria, 86 were treated with helium ions and 98 with 125I brachytherapy.

RESULTS

No patients with uveal melanoma had a history of systemic malignancy. Tumors were less than 15 mm in maximum diameter and less than 10 mm in thickness. A minimum tumor dose of 70 GyE was delivered to the tumor apex. There was a significantly higher local recurrence rate after 125I brachytherapy than after helium-ion irradiation. Enucleations occurred more frequently after brachytherapy (relative risk = 1.99; 95% confidence interval, 0.78-5.78). More anterior segment complications occurred after helium-ion irradiation. To date, there has been no measurable impact on survival.

CONCLUSIONS

Most uveal melanomas can be managed with radiation with retention of the eye. There was better tumor control with helium-ion irradiation; however, there were more anterior segment complications.

Klippel-Trenaunay syndrome and cutaneous carcinomas

A patient with Klippel-Trenaunay syndrome who developed basal cell and squamous cell carcinomas on the limb affected by the vascular malformation, is reported. The nature of this association is discussed.

CT characteristics of patients with brain metastases treated in RTOG study 79-16

The search continues for a favorable subgroup of patients with brain metastases in whom testing of new modalities might show a benefit in overall survival. Complete pre- and post-treatment CT evaluation of the brain was performed in 779 of the 859 patients entered into RTOG protocol 7916, a phase III study of the role of misonidazole combined with radiation therapy in the treatment of brain metastases. Pretreatment scan findings of mass effect, midline shift, massive edema, central necrosis, location of sentinel lesion, and number of lesions were correlated with length of survival for all patients as well as for each treatment group. The only characteristics that showed a statistically significant difference in survival in the overall group were the presence of < or = 3 lesions and the presence of a midline shift. The actual benefit in overall survival, however, was found to be only 3 weeks. The volume of the largest lesion prior to treatment did not correlate well with survival, nor did location of lesions. The time to response, number of responders and absolute decrease in number of lesions were similar for the four treatment arms. Patients who responded to cranial treatment had a significantly prolonged survival over those who did not respond. No CT characteristic evaluated in this study showed value as a clinically relevant prognosticator for patients with brain metastases for the overall group. Patients who fulfilled three of the four favorable clinical characteristics previously described by Diener-West (age < or = 60, KPS > or = 70, primary lesion absent or controlled and brain as sole site of metastasis), were analyzed separately. Those with < or = three lesions had a statistically significantly prolonged survival over those with four or more lesions.

Voices from family medicine: Theodore Phillips. Interview by William B. Ventres and John J. Frey

Ted Phillips has had a remarkable career in medicine. He practiced in a rural Alaskan town, helped build the University of Washington's Department of Family Medicine as its founding chair, labored as an associate and acting dean at the university, and, more recently, returned to clinical practice part time on a small island in Washington state and travels to the University of Washington to direct the course on introduction to clinical medicine. Dr. Phillips was president of the Society of Teachers of Family Medicine in 1978-1979 and received the Society's Certificate of Excellence in 1981. He currently serves as the only community-based physician on the National Advisory Council of the Agency for Health Care Policy and Research. This transcript is an abridged version of interviews conducted in April and June 1992.

Detection of feline immunodeficiency virus (FIV) nucleic acids in FIV-seronegative cats

A study was undertaken to determine the rate of viral transmission among naive specific-pathogen-free (SPF) cats living in close contact with feline immunodeficiency virus (FIV)-infected cats. Twenty SPF cats were housed in the same rooms with experimentally FIV-infected seropositive and virus culture-positive cats for 2 to 4 years and were monitored for the presence of FIV nucleic acids and antibodies. Only 1 of the 20 cats became seropositive and virus culture positive and developed signs of disease. Genomic DNA from bone marrow and peripheral blood mononuclear cells (PBMC) of 10 of 19 healthy-appearing seronegative cats became positive for FIV DNA by the polymerase chain reaction. Twenty-eight SPF cats housed as groups in separate quarters and never exposed to FIV-infected cats were uniformly negative for FIV DNA. FIV RNA transcripts were detected in concanavalin A-stimulated PBMC cultures from 4 of 10 FIV DNA-positive, seronegative cats by in situ hybridization. PBMC from three of four naive SPF cats acquired FIV nucleic acids after the cats were transfused with blood and bone marrow from FIV genome-positive, seronegative donors. Three of five FIV-seronegative cats housed for years with naturally FIV-infected cats in a private household were also found to harbor FIV DNA, indicating that the same phenomenon occurred in the field. These findings demonstrate that cats living in close contact with FIV-infected seropositive cats can acquire FIV nucleic acids without developing detectable levels of serum antibodies or disease.