The clinically negative neck in patients with early oral cavity carcinoma: a decision-analysis approach to management

Despite improvements in both diagnostic and therapeutic techniques in recent decades, the prognosis for oral cavity squamous cell carcinoma has not improved. Patients presenting with overt regional metastases necessarily undergo therapeutic intervention directed to both the primary site and the neck. However, controversy persists regarding the best management for patients without clinical evidence of nodal disease. Would these patients best be managed with elective treatment of the neck, with no neck treatment unless overt nodal metastases are detected, or would some diagnostic test be beneficial in determining which patients are at highest risk of having occult nodal disease and, therefore, most likely to benefit from elective treatment? We performed a decision analysis to address this question. Baseline probability assumptions were made based on the evidence available in the literature for the parameters of interest. A decision tree was constructed and analyzed. In the final analysis, two options, elective functional neck dissection for all patients and a supraomohyoid neck dissection, were equally beneficial and were significantly better than the remaining options tested. Either of these surgical treatment strategies shifted the survival distribution curve significantly to the right.

Desensitization of gonadotropin-releasing hormone action in the gonadotrope-derived alpha T3-1 cell line

Sustained exposure of gonadotropes to GnRH causes a pronounced desensitization of GnRH-stimulated gonadotropin release, but the mechanisms involved are poorly understood. Recent studies have suggested, however, that GnRH-stimulated phosphoinositidase C (PIC) activity does not undergo rapid ( < 5 min) homologous desensitization in alpha T3-1 cells, and we have, therefore, used this cell line to address the question of whether desensitization occurs distal to PIC activity and/or in an intermediate time frame. We show that GnRH stimulates a rapid increase in inositol 1,4,5-trisphosphate [Ins(1,4,5)P3; maximum at 10-20 sec with a modest reduction thereafter] and that the GnRH-stimulated accumulation of [3H]IPs (in cells stimulated in the presence of LiCl) increases linearly over 5-300 sec. This clearly indicates that desensitization of PIC does not occur within this period and that the dramatic reduction in the rate of Ins(1,4,5)P3 accumulation (10-30 sec) is due to its metabolism, rather than to a reduction in Ins(1,4,5)P3 generation. Pretreatment for 60 min with 10(-7)M GnRH reduced cell surface GnRH receptor number by 48% (without measurably altering Kd). The pretreatment also reduced maximal GnRH-stimulated [3H]IP accumulation (to 66% of the control) and increased the EC50 for GnRH-stimulated [3H]IP accumulation approximately 3-fold, demonstrating that desensitization of GnRH-stimulated [3H]IP accumulation can, indeed, occur within 60 min, but that this may be attributable to receptor loss (without appreciable uncoupling of residual receptors from their immediate effector system). Pretreatment for 60 min with GnRH also caused a dose-dependent reduction in both spike and plateau phases of the GnRH effect on cytosolic Ca2+. This effect could not be overcome by stimulation with high concentrations of GnRH and appears, therefore, to reflect not only receptor loss, but, also, an additional inability of agonist-occupied GnRH receptors to elevate cytosolic Ca2+. The effect of KCl on cytosolic Ca2+ was similarly reduced by GnRH pretreatment, suggesting that desensitization of voltage-operated Ca2+ channels mediates desensitization of the plateau phase Ca2+ response to GnRH. Such a mechanism could not, however, explain desensitization of the spike phase of the Ca2+ response to GnRH seen in normal or Ca2+ -free medium. Accordingly, the data reveal a novel mechanism for homologous desensitization to GnRH in which agonist-occupied GnRH receptors are rendered unable to mobilize intracellular Ca2+ and imply that desensitization of GnRH-stimulated Ins(1,4,5)P3 production and/or action occurs.

Meeting of minds in psychiatry and homeopathy: an example in social phobia

Communication between homeopaths and the biomedical community can be enhanced by an interpretation of the homeopathic repertory in light of current medical diagnostic terminology. This report reviews the current, conventional symptom formulation for social phobia, the third most common psychiatric diagnosis in the US community. Eighty-three rubrics in the homeopathic materia medica corresponding to symptoms of social phobia were identified and then used in a computerized repertorizing program to identify potential homeopathic remedies for social phobia. Although Kent's Repertory describes many symptoms of social phobia, the terminology should be updated, and there is a surprising lack of information about some key rubrics. Clinical judgment is always needed to interpret the significance of symptoms that could be caused by more than one pathogenic mechanism. Although many of the remedies traditionally thought to be useful in treating patients with social phobia do indeed appear in the computerized Repertory search, additional remedies emerged, including both polycrests and small remedies, which may have a place in treating this disorder.

Emphysematous cystitis presenting as painless gross hematuria

A case of emphysematous cystitis in an immunocompetent male is described. The diagnosis is generally rare, but may be made in the Emergency Department. A history of pneumaturia is highly suggestive of the entity, but is rarely offered by the patient. The evaluation and management of emphysematous cystitis are discussed.

The free flap and plate in oromandibular reconstruction: long-term review and indications

The purpose of this study was to define the role of reconstruction plates as bone replacement in oromandibular reconstruction. From 1987 through 1991, 71 consecutive oral cancer patients underwent composite resection and reconstruction and were entered into one of two studies. In the first study of 31 patients, 15 underwent oromandibular reconstruction using a radial forearm osteocutaneous flap, while the remainder (16) received a radial forearm fasciocutaneous flap together with a mandibular reconstruction plate. The second study involved 40 subsequent patients, all receiving the latter form of reconstruction. Twenty-one of the plates were stainless steel, and the remaining 19 were of the titanium hollow screw (THORP) type. We followed the patients prospectively. We defined success as a reconstruction that we did not have to remove. Additionally, since the patients had limited life expectancy, we developed the idea of days of life lost and incorporated it into our definition of a successful outcome. Vascularized autogenous bone proved to be more successful than metallic plates used alone in terms both of reconstruction survival and of minimizing days of life lost. The overall success rate of mandibular plate reconstruction was 78.9 percent, but analysis by defect type revealed a failure rate of 35 percent when the defects were anterior and only 5 percent when they were lateral. THORP plates demonstrated a trend towards more durability. We would now recommend plate reconstruction only in lateral defects in patients with a poor prognosis.

Lack of influence of non-inherited maternal HLA-DR alleles on susceptibility to rheumatoid arthritis

OBJECTIVE

To reproduce findings from previous reports that non-inherited maternal HLA class II antigens might contribute to rheumatoid arthritis (RA) susceptibility in the offspring.

METHODS

Families were recruited from the Arthritis and Rheumatism Council's National Repository of RA families and HLA-DRB1 alleles were examined in these individuals and their first degree relatives using DNA typing methods.

RESULTS

There was no evidence of an increase in either non-inherited maternal HLA-DR4 or the HLA-DRB1 shared epitope as a whole compared with the frequency expected using the non-inherited paternal antigens as controls.

CONCLUSIONS

The numbers of probands who were shared epitope negative were small, but we are unable to confirm in these families the findings that non-inherited maternal HLA contributes an additional susceptibility factor to rheumatoid arthritis.

Multisite oligonucleotide-mediated mutagenesis: application to the conversion of a mitochondrial gene to universal genetic code

Using multisite oligonucleotide-mediated mutagenesis in conjunction with a mutagenesis selection procedure and rapid screening by allele-specific oligonucleotide hybridization has allowed us to develop a reliable protocol that enables a large number of base changes to be introduced rapidly into a piece of DNA, with the minimum number of manipulations. We have applied this protocol to generate synthetic versions of four mouse mitochondrial genes capable of being expressed in the nucleus/cytosol.

Long-term safety and clinical acceptability of venlafaxine and imipramine in outpatients with major depression

The antidepressant efficacy and safety of venlafaxine was shown previously in 6-week, placebo-controlled trials. We evaluated the long-term safety and clinical acceptability of venlafaxine and imipramine in a double-blind, parallel-group, comparative study. Two hundred ninety depressed outpatients were treated with venlafaxine, and an additional 91 received imipramine for as long as clinically necessary, up to 1 year. The total daily dose of each drug could vary from 75 to 225 mg. The Clinical Global Impressions Scale and a therapeutic response rate that was based on Clinical Global Impressions Scale-Improvement and incorporated discontinuation information were used to evaluate efficacy. Safety determinations and patient subjective ratings were used to evaluate safety and clinical acceptability. During the study, the adverse events were generally mild to moderate and most subsided with continued treatment; the most frequent were nausea for venlafaxine and dry mouth for imipramine. The anticholinergic side effect burden was significantly higher in the imipramine group than in the venlafaxine group. Venlafaxine was judged significantly more acceptable than imipramine, on the basis of the subjective ratings by patients. Fewer venlafaxine-treated patients than imipramine-treated patients withdrew because of adverse events and unsatisfactory response. There was a consistent trend in the therapeutic response rates in favor of venlafaxine that reached statistical significance at months 2, 6, and 12. In this long-term study, patient acceptability was greater for venlafaxine than for imipramine, suggesting therapeutic advantages for venlafaxine in the long-term treatment of depression. Additional studies with other active comparators are underway to confirm and extend these encouraging results.

Tissue ablation by a free-electron laser tuned to the amide II band

Efforts to ablate soft tissue with conventional lasers have been limited by collateral damage and by concern over potential photochemical effects. Motivated by the thermal-confinement model, past infrared investigations targeted the OH-stretch mode of water with fast pulses from lasers emitting near 3,000 nm (refs 1, 7-9). What does a free-electron laser offer for the investigation of tissue ablation? Operating at non-photochemical single-photon energies, these infrared sources can produce trains of picosecond pulses tunable to the vibrational modes of proteins, lipids and/or water. We report here that targeting free-electron laser radiation to the amide II band of proteins leads to tissue ablation characterized by minimal collateral damage while maintaining a substantial ablation rate. To account for these observations we propose a novel ablation mechanism based on compromising tissue through resonant denaturation of structural proteins.

The cytoplasmic domain mediates localization of furin to the trans-Golgi network en route to the endosomal/lysosomal system

To investigate the mechanisms of membrane protein localization to the Golgi complex, we have examined the intracellular trafficking of epitope-tagged forms of the mammalian endopeptidase, furin, in stably transformed rat basophilic leukemia cells. Our studies show that furin is predominantly localized to the trans-Golgi network (TGN) at steady state, with smaller amounts present in intracellular vesicles. Biochemical and morphological analyses reveal that furin is progressively delivered to a lysosomal compartment, where it is degraded. Analyses of furin deletion mutants and chimeric proteins show that the cytoplasmic domain is both necessary and sufficient for localization to the TGN in various cell types. Interestingly, deletion of most of the cytoplasmic domain of furin results in a molecule that is predominantly localized to intracellular vesicles, some of which display characteristics of lysosomes. To a lesser extent, the cytoplasmically deleted molecule is also localized to the plasma membrane. These observations suggest the existence of an additional determinant for targeting to the endosomal/lysosomal system within the lumenal and/or transmembrane domains of furin. Thus, the overall pattern of trafficking and steady state localization of furin are determined by targeting information contained within more than one region of the molecule.

Low levels of ATP synthase and cytochrome c oxidase subunit peptide from hearts of copper-deficient rats are not altered by the administration of dimethyl sulfoxide

This study determined if reported decreases in the delta subunit of ATP synthase and nuclear-encoded cytochrome c oxidase subunits in hearts of copper-deficient rats were secondary to the heart disease pathology or due to lack of the trace element. Male weanling Long-Evans rats were randomly divided into six groups: rats fed a copper-adequate or copper-deficient diet (with free access) with or without 5% dimethyl sulfoxide (DMSO) in the drinking water and rats pair-fed the copper-adequate or copper-deficient diet without DMSO treatment. After 4 wk, rats in the groups fed the copper-deficient diet had lower liver superoxide dismutase and heart cytochrome c oxidase activities compared with groups fed the copper-adequate diet. Administration of DMSO, an antioxidant, and energy restriction (pair-feeding) partially blocked cardiac hypertrophy in rats fed the copper-deficient diet. Greater mitochondrial volume density and mitochondrial:myofibrillar ratio and disrupted myofibrils and basal laminae were observed in the hearts from rats fed the copper-deficient diet and not treated with DMSO compared with hearts from groups fed the copper-adequate diet. The DMSO-treated rats fed the copper-deficient diet had hearts with intact structure but enlarged mitochondria compared with other groups fed the copper-deficient diet. The delta subunit of ATP synthase and the nuclear-encoded cytochrome c oxidase subunits IV and V were depressed in rats fed a copper-deficient diet regardless of antioxidant treatment and pair-feeding. These data suggest that the effects of copper deficiency upon ATP synthase and cytochrome c oxidase proteins are not due to the cardiac pathology.

"Homozygosity" for the HLA-DR shared epitope contributes the highest risk for rheumatoid arthritis concordance in identical twins

OBJECTIVE

To assess the contribution of HLA-DRB1 alleles in determining rheumatoid arthritis (RA) concordance in monozygotic twins.

METHODS

Ninety-one monozygotic twins pairs in which at least 1 twin was affected were typed for HLA-DRB1 using both serologic methods and polymerase chain reaction amplification with sequence-specific oligonucleotide hybridization. The role of DR4 and of the shared epitope in disease concordance was investigated. Relative risks (RR) with 95% confidence intervals were determined.

RESULTS

Increased concordance for RA was observed in both DR4 positive and shared epitope positive pairs (RR 3.4 and 3.7, respectively). A 5-fold risk for RA concordance was seen in twins who were "homozygous" for the shared epitope, compared with those negative for the shared epitope.

CONCLUSION

In the absence of the shared epitope, RA concordance in monozygotic twins is rare. In contrast, "homozygosity" for the shared epitope is the most important factor in determining RA concordance.