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R J Campbell

Publications and source records attributed to R J Campbell.

At least 19 recordsLinked to original sources
PubMed1996

Succinate dehydrogenase activity within synaptic and extrasynaptic compartments of functionally-overloaded rat skeletal muscle fibers.

Activity of the mitochondrial enzyme succinate dehydrogenase (SDH) was assessed using quantitative microphotometric techniques within postsynaptic, subsarcolemmal and intermyofibrillar compartments of overloaded soleus muscle fibers. Six weeks of overload, induced via synergist tenotomy, significantly increased soleus muscle mass (23%) and mean fiber cross-sectional area (17%). Despite these increases in cell size, SDH activity within all three intracellular compartments of overloaded muscle fibers was not different from levels in corresponding regions of control fibers. Thus, we show for the first time that activity-related increases in muscle cell volume, and specifically motor endplate area, appear to be coordinated with increased levels of oxidative enzymes within distinct subcellular compartments, including the postsynaptic sarcoplasm.

Animals↗
PubMed1996

Regulation of succinate dehydrogenase within muscle fiber compartments by nerve-mediated activity and CNTF.

We investigated the regulatory effects of neural activation and trophic factors on the selective accumulation of succinate dehydrogenase (SDH; EC 1.3.99.1) activity at the endplate, as well as within subsarcolemmal and intermyofibrillar regions of rat soleus muscle fibers. The role of activation was assessed by stimulation of tetrodotoxin (TTX)-inactivated nerves distal to the site of drug application. We also studied whether ciliary neurotrophic factor (CNTF) is involved in regulating the postsynaptic accumulation of SDH. Using quantitative microphotometry, we found that daily stimulation of quiescent but intact nerves prevented the TTX-induced decrease in SDH activity within extrajunctional regions, whereas, at the endplate, the counteraction was partial (30%). Thus it appears that endplate levels of this enzyme are regulated by a complex mechanism involving an interaction between neuromuscular activation and trophic factors. We also found that daily CNTF administration counteracted the denervation-associated loss of SDH activity exclusively within the intermyofibrillar compartment, suggesting that CNTF treatment mimics the effects of activity on SDH levels within the core region of denervated fibers, but under these conditions does not influence the endplate accumulation of this enzyme.

Animals↗
PubMed1995

Nerve-dependent regulation of succinate dehydrogenase in junctional and extrajunctional compartments of rat muscle fibres.

1. We studied the distribution of the mitochondrial enzyme succinate dehydrogenase (SDH) within junctional and extrajunctional compartments of rat soleus muscle fibres. Using quantitative microphotometric imaging techniques, we showed that the motor endplate region of soleus fibres displays SDH activity that is two- and threefold higher than in subsarcolemmal (SS) and intermyofibrillar (IM) compartments, respectively, and that essentially all endplate SDH activity is of postsynaptic origin. 2. In addition, we examined the influence of the motor nerve on the regulation of this enzyme within these compartments using denervation and tetrodotoxin (TTX)-induced blockade of nerve impulse conduction. Both models of short-term muscle paralysis reduced SDH activity to a comparable extent (approximately 30%) in both the SS and IM compartments, suggesting that expression of this enzyme is co-ordinately regulated in these two regions. Alternatively, denervation and TTX inactivation led to distinct alterations at the level of the motor endplate. SDH activity at denervated endplates was dramatically reduced (by 60%) in comparison to controls, whereas at endplates of TTX-inactivated counterparts, this reduction was significantly less (35%). 3. These findings suggest that motor activity per se is the key factor regulating expression of SDH in non-innervated regions of muscle fibres and that accumulation of SDH activity within the postsynaptic sarcoplasm is equally subject to local mechanisms involving nerve-derived trophic factors.

Animals↗
PubMed1995

Clinicopathologic correlation of a case of adenocarcinoma of the retinal pigment epithelium.

PURPOSE/METHODS: We observed a clinicopathologic correlation of a case of adenocarcinoma of the retinal pigment epithelium. RESULTS/CONCLUSIONS: The ultrasonographic findings of this tumor demonstrated a collar button profile with high internal reflectivity. The ultrasonographic characteristics in this case reflected the variable vascularity and cystic spaces within the tumor.

Adenocarcinoma↗
PubMed1995

Immunolocalization of calcitriol receptor, plasma membrane calcium pump and calbindin-D28k in the cornea and ciliary body of the rat eye.

Epitopes of the calcitriol receptor, the ATP-dependent plasma membrane calcium pump (PMCA) and the 28-kD vitamin-D-dependent Ca-binding protein (calbindin-D28k) were detected in sections of the albino rat eye using light microscopy and immunohistochemistry of paraffin-embedded tissues. Calcitriol receptor and calbindin-D28k epitopes were detected in both the inner and outer layers of the ciliary body epithelium. PMCA was present in both epithelial cell layers of the ciliary body but was most prominent in the inner layer. Corneal epithelium and endothelium also contained epitopes for calcitriol receptor, PMCA and calbindin-D28k. These Ca-regulatory proteins may play a role in the cellular physiology of the albino rat eye by maintaining appropriate intracellular and aqueous humor Ca concentrations.

Animals↗
PubMed1995

Immuno-localization of the calcitriol receptor, calbindin-D28k and the plasma membrane calcium pump in the human eye.

Using immunohistochemical methods, we detected epitopes of the calcitriol receptor, the ATP-dependent plasma membrane calcium pump and the 28kD vitamin D-dependent calcium-binding protein in sections of the human eye. In retinal photoreceptors, vitamin D receptor, plasma membrane calcium pump and calcium-binding protein epitopes were detected in the outer nuclear layer. Epitopes for the vitamin D receptor and the calcium-binding protein were present in the inner and outer segments of the photoreceptors, where visual transduction occurs. All three proteins were detected in some cells of the ganglion cell layer, the inner nuclear layer, and the retinal pigment epithelium. Epitopes for these proteins also were noted in the ciliary body epithelium. VDR epitopes were seen in lens epithelium. Some immunostaining for VDR, PMCA and calbindin-D28k also was present in the endothelium and in the basal epithelium of the cornea. The presence of these proteins in several tissues of the human eye suggests that the proteins may play a role in the cellular physiology of the eye. Their exact functions in the eye remain undetermined.

Antibodies, Monoclonal↗
PubMed1994

A review of 340 orbital tumors in children during a 60-year period.

We reviewed cases of histopathologically verified orbital tumors in children at our institution over 60 years to determine the distribution of various pathologic processes and trends over time. We studied the medical records and pathology specimens from 340 patients aged 18 years or younger who underwent biopsy for orbital mass from 1932 through 1991. The most common tumors were cysts (79 of 340, 23.2%), vascular lesions (60 of 340, 17.6%), optic nerve and meningeal neoplasms (56 of 340, 16.5%), inflammatory masses (29 of 340, 8.5%), osseous and fibrocystic lesions (27 of 340, 7.9%), and rhabdomyosarcomas (24 of 340, 7.1%). The overall frequency of malignancies was 18.2% (62 of 340): 11.5% (39) were primary tumors and 6.8% (23) were secondary and metastatic. The frequency of orbital malignancies was 25.4% (36 of 142) in the first 30 years (1932 through 1961) and 13.1% (26 of 198) in the second 30 years (1962 through 1991). The percentage of primary orbital malignancies was almost identical during the first and second periods (11.9% [17 of 142] and 11.1% [22 of 198], respectively). However, secondary and metastatic orbital neoplasms occurred in 13.4% (19 of 142) of the patients during the first 30 years and in only 2.0% (four of 198) during the second 30 years. The frequency of primary orbital malignancies in biopsy material remained the same over 60 years. However, the overall incidence of orbital biopsy specimens containing a malignancy decreased as a result of a reduction in the number of secondary and metastatic neoplasms that underwent biopsy.

Child↗
PubMed1994

Coccidioidomycosis with necrotizing granulomatous conjunctivitis.

A patient with a steroid-resistant conjunctival nodule developed severe necrotizing granulomatous conjunctivitis during aggressive treatment with topical, subconjunctival, and systemic steroids. Culture of the tissue yielded Coccidioides immitis. A cavitary lesion was noted on a chest radiograph, and the same organism was recovered from a lung biopsy specimen. The granulomatous conjunctivitis was controlled only after aggressive debridement of the affected area and months of treatment with topical amphotericin B and oral fluconazole. A review of the literature suggests that subclinical ocular involvement from pulmonary coccidioidomycosis may be more common than generally believed. Conditions that blunt the host immune response may lead to a higher incidence of clinically significant ocular involvement.

Aged↗
PubMed1993

Optic nerve sheath decompression for visual loss in patients with acquired immunodeficiency syndrome and cryptococcal meningitis with papilledema.

Visual dysfunction developing in association with acquired immunodeficiency syndrome (AIDS) can be multifactorial. Two patients with this syndrome and cryptococcal meningitis had papilledema and visual loss. Both were treated by optic nerve sheath fenestration. One patient had bilateral nonsimultaneous optic nerve sheath fenestrations; visual function improved in one eye. The other patient had bilateral visual improvement after a unilateral optic nerve sheath fenestration. Cryptococcal organisms were present in the dural sheath specimens of both patients despite ongoing therapy with antifungal medication. Postoperative orbital infectious complications did not occur. Autopsy examination of one patient showed that the sites of fenestration were patent. Medical treatment of cryptococcal meningitis associated with AIDS has a guarded prognosis. Optic nerve sheath fenestration offers a treatment alternative for papilledema and visual loss that occur with cryptococcal meningitis.

AIDS-Related Opportunistic Infections↗
PubMed1993

Pathologic findings in the retinal pigment epitheliopathy associated with the amyotrophic lateral sclerosis/parkinsonism-dementia complex of Guam.

BACKGROUND: A pigment epitheliopathy that resembles ophthalmomyiasis interna occurs in approximately 10% of a large sample of the Chamorro population of Guam age 39 years or older; the rate is approximately 50% among those who have amyotrophic lateral sclerosis or Parkinsonism-dementia complex (lytico bodig). METHODS: Since publication of an earlier clinical report of affected patients, several of them have died of their neurologic disease, and their eyes were obtained for pathologic study. This is the first pathologic report of the retinal pigment epitheliopathy seen in the setting of amyotrophic lateral sclerosis/Parkinsonism-dementia complex of Guam and is based on examination of 13 eyes from 7 patients. RESULTS/CONCLUSION: Focal areas of attenuation of the retinal pigment epithelium in association with a reduced amount of intracellular pigment correlated with the funduscopic and gross appearance. No larvae were seen, and there was no evidence of inflammation. The pathogenesis of this pigment epitheliopathy remains undetermined.

Amyotrophic Lateral Sclerosis↗
PubMed1993

Varicella-zoster virus retinitis in a patient with AIDS-related complex: case report and brief review of the acute retinal necrosis syndrome.

Retinitis reminiscent of the acute retinal necrosis syndrome was recognized in a patient with AIDS-related complex after he had experienced several episodes of a sacral, dermatomic zosteriform eruption. Varicella-zoster virus (VZV) was subsequently recovered from cell culture of retinal tissue. The literature on VZV retinitis, including that on acute retinal necrosis, is reviewed. Dissemination of VZV infection in AIDS is also reviewed. Features that differentiate the findings and course of VZV retinitis in patients with AIDS from those in otherwise healthy adults are noted and related to potentially different pathogenic mechanisms. This unusual and recently recognized complication of herpesvirus infection may be promoted by AIDS-related immunosuppression. Acute retinal necrosis and other more-recently described forms of VZV retinitis, which have primarily been subjects of the ophthalmologic literature, merit the attention of clinicians and investigators of infectious diseases.

AIDS-Related Complex↗
PubMed1993

Potency in groups: articulating a construct.

This paper examines potency, defined as the collective belief in a group that it can be effective, and its role in determining group effectiveness. The paper illustrates the construct and reviews its origins. The distinctiveness of potency from efficacy and from other collective and motivational constructs is described. The measurement of potency is also examined. The paper concludes with a presentation of a conceptual framework for understanding the determinants of potency and with a discussion of future theory, research and practice.

Attitude↗
PubMed1992

Diagnostic value and limitations of orbital biopsy in Wegener's granulomatosis.

Patients with Wegener's granulomatosis may present with ophthalmic involvement in either the classic or limited forms. Although the overall clinical picture and serologic testing for antineutrophil cytoplasmic antibody (ANCA) are important, biopsy is often necessary for a definitive diagnosis. Accurate interpretation of these orbital biopsies is essential. The authors reviewed the histopathologic features of 13 orbital biopsies in patients with well-documented Wegener's granulomatosis. The classic triad of vasculitis, tissue necrosis, and granulomatous inflammation was seen in 7 of 13 biopsies (54%). Vasculitis in combination with other microscopic findings was seen in 4 of 13 (31%) biopsies. Giant cells were seldom seen. Two biopsies showed only perivascular infiltrates. Based on this study, it appears that a spectrum of histopathologic features can be seen in orbital biopsies in Wegener's granulomatosis. This study underscores the importance of clinical correlation, the application of the ANCA test, and comparison with extraorbital biopsies, if available, when interpreting orbital biopsies in the diagnosis of Wegener's granulomatosis.

Adolescent↗
PubMed1991

Isolated neurofibromas of the conjunctiva.

We studied four histologically verified cases of isolated neurofibromas of the conjunctiva. The histologic pattern was diffuse in two patients, plexiform in one patient, and solitary in one patient. Simple excision was curative in all cases. We emphasize the importance of distinguishing neuromas (which may be associated with multiple endocrine neoplasia) from neurofibromas.

Adolescent↗
PubMed1991

An eyelash nidus for dacryoliths of the lacrimal excretory and secretory systems.

We treated two patients with dacryolithiasis secondary to an eyelash. The first patient underwent dacryocystorhinostomy for a stone within the lacrimal sac. In the second patient the dacryolith was removed from a lacrimal gland ductule. Eyelashes found in the tear film or conjunctival fornices during routine examination should be removed to prevent the possible occurrence of dacryolithiasis.

Adult↗
PubMed1991

Aspergillus terreus endophthalmitis in a patient with chronic lymphocytic leukemia.

A 65-year-old woman with a 7-year history of chronic lymphocytic leukemia presented with acute visual loss, pain, and redness in her right eye. Results of stains and cultures of anterior chamber fluid were negative. Neurologic problems, bronchopulmonary pneumonia, recurrent skin lesions, and a low-grade fever developed. Progressive respiratory distress ensued, and the patient died 1 month after presentation. Cultures from antemortem sputum and skin samples were positive for Aspergillus terreus. Postmortem histologic results showed extensive A terreus invasion of the posterior vitreous, retina, choroid, and anterior optic nerve. This organism was also found in histologic sections from the right adrenal gland, left kidney, thyroid, urinary bladder, right lung, skin, esophagus, sputum, vessels of the myocardium, and brain. To our knowledge, A terreus endophthalmitis has not been reported previously.

Aged↗