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Biomedical subjects

C G Jackson

Publications and source records attributed to C G Jackson.

At least 91 records · Page 5Linked to original sources
PubMed1987

The surgical treatment of skull-base tumors with intracranial extension.

As a discipline, skull-base surgery via the transtemporal route has matured since 1975. Previously considered unresectable, skull-base tumors with intracranial extension can now be successfully removed by means of modification of contemporary exposures with neurosurgical collaboration. Between September 1970 and February 1986, 126 skull-base tumors have been operated on by The Otology Group, P.C. Of these, 49 had intracranial extension. In this article, techniques for tumor removal and dural defect reconstruction are outlined. A single-staged procedure is advised. The advantages of and exceptions to this format are described. Techniques that will prevent postoperative cerebrospinal fluid leakage are highlighted. Results and complications of this surgical series are discussed, and team aspects of this surgery are emphasized.

Adolescent↗
PubMed1987

Fiber composition and capillarity in growing guinea pigs acclimated to cold and cold plus hypoxia.

The central portion of the medial head of the gastrocnemius of control (normoxic and normothermic), hypoxia-, cold-, and cold plus hypoxia-acclimated guinea pigs was analyzed for capillary supply and fiber composition to elucidate changes in capillarity induced by environmental stresses. The muscle was cut at midbelly, frozen, sectioned, and stained for myosin ATPase. Fiber cross-sectional areas; percentages of slow-twitch oxidative (SO), fast-twitch oxidative-glycolytic (FOG), and fast-twitch glycolytic (FG) fibers; and numbers of capillaries around each fiber type were measured. Growth rates of all four guinea pig groups were similar. Capillarity was not affected by acclimation to hypoxia. Cold and cold plus hypoxia acclimation led to increased numbers of capillaries around the fiber in all three fiber types. In addition, significant increases in the percentage of FOG fibers and concomitant decreases in the percentage of FG fibers compared to controls were found in cold and in cold plus hypoxia indicating that a transformation of fiber type from FG to FOG had occurred. The increase in FOGs at the expense of the FGs did not occur in the guinea pigs grown in a hypoxic environment. The increased total capillarity in those muscles studied was the result of more capillaries around all fiber types and was not due to simple transformation of fibers.

Acclimatization↗
PubMed1987

Hemangioma of the middle ear.

A 13-month-old child was seen and evaluated for persistent aural bleeding following the placement of a pressure equalizing tube. A vascular mass was identified in the middle ear space. The radiologic evaluation is discussed. The mass was surgically resected for both diagnostic and therapeutic reasons. Pathologic examination revealed a benign hemangioma. The significance of this diagnosis is discussed.

Diagnostic Errors↗
PubMed1986

Characterization of primate bronchoalveolar mast cells. I. IgE-dependent release of histamine, leukotrienes, and prostaglandins.

Large numbers of functional mast cells were obtained by bronchoalveolar lavage (BAL) of Macaca arctoides monkeys that had been infected with the nematode Ascaris suum. These lavage cells, of which 21% were mast cells, released histamine, LTC4, and PGD2 in a concentration-dependent fashion when challenged with ascaris antigen or antibody to human IgE. However, there was no release of histamine when these cells were challenged with compound 48/80. The amount of mediator released was highly dependent on the sensitivity of the cells to immunologic challenge, but was generally in the range of 2 to 5 micrograms histamine (30 to 70% of total), 20 to 80 ng LTC4, and 100 to 300 ng PGD2 per 10(6) mast cells when maximally challenged. Other eicosanoids measured were released only in much smaller quantities. Maximal values were 4 ng LTB4, 2 ng PGE2, and approximately 10 to 20 ng PGF2 alpha per 10(6) mast cells. The amount of LTC4 and PGD2 released correlated with the release of histamine, the calculated regression line indicating that 18 ng LTC4 and 50 ng PGD2 were released per microgram of histamine released. This correlation suggests that the majority of the LTC4 and PGD2 released was probably mast cell-derived. Further support for this conclusion was given by the observation that when lavage cells were fractioned on continuous Percoll gradients, the ability to release LTC4 and PGD2 on immunologic challenge coincided with the peak of mast cells.

Animals↗
PubMed1986

Characterization of primate bronchoalveolar mast cells. II. Inhibition of histamine, LTC4, and PGD2 release from primate bronchoalveolar mast cells and a comparison with rat peritoneal mast cells.

As described in the preceding companion paper, bronchoalveolar lavage (BAL) of the primate Macaca arctoides infected with the nematode Ascaris suum yields a population of cells containing a high proportion of mast cells (21%). Nedocromil sodium, a new drug undergoing clinical evaluation for the treatment of reversible obstructive airways disease, inhibited the release of histamine, LTC4, and PGD2 from these cells challenged with antigen (with IC30 values of 2.1 X 10(-6) M, 2.3 X 10(-6) M, and 1.9 X 10(-6) M, respectively) and with anti-human IgE (IC30 values of 4.7 X 10(-6) M, 1.3 X 10(-6) M, and 1.3 X 10(-6) M, respectively). Cromolyn sodium was essentially inactive. Histamine release from rat peritoneal mast cells induced by anti-rat IgE was, however, inhibited by both nedocromil sodium and cromolyn sodium with IC30 values of 1.1 X 10(-6) M and 5.5 X 10(-7) M, respectively. Both compounds induce phosphorylation of a 78,000 m.w. protein in the rat peritoneal mast cell in the absence of any stimulus at the same concentrations as those required to inhibit histamine release stimulated by anti-IgE. This event may be part of a feedback mechanism to limit degranulation. Nedocromil sodium and cromolyn sodium were equipotent in their ability to inhibit anti-IgE-induced histamine release from rat peritoneal mast cells, but differed markedly in their ability to inhibit histamine release from macaque BAL cells.

Animals↗
PubMed1986

pHG165: a pBR322 copy number derivative of pUC8 for cloning and expression.

During the construction of the Messing pUC plasmid series, the rop(rom) gene of pBR322 which mediates the activity of RNAI was deleted. This has resulted in an elevated copy number for the pUC plasmids which makes the expression of beta-galactosidase activity constitutive in a host containing the Iqtss lac repressor. We describe the construction of a new series of vectors which retain the pUC multiple cloning site (MCS) but in which copy number control has been recovered. In addition, the lac alpha/lac promoter expression region has been inserted into a HpaI cassette. This facilitates the movement of recombinant DNA clones within the MCS. It also increases the complementation activity of the lac alpha peptide by an order of magnitude, allowing selection of recombinants by their Lac- phenotype on MacConkey agar.

Bacterial Proteins↗
PubMed1986

Facial reanimation with the VII-XII anastomosis: analysis of the functional and psychologic results.

The VII-XII anastomosis has been employed for more than a decade by The Otology Group, P.C., in the facial reanimation of patients undergoing extirpation of tumors involving the cerebellopontine angle and the skull base. A retrospective review based upon a detailed questionnaire and submitted photographic documentation from 61 patients forms the basis for this review. Details and analysis of the functional results include onset of function, synkinetic activity, corneal irritation and associated ophthalmologic problems, facial tone and symmetry, and volitional mimetic function. From a psychosocial perspective, evaluation was made regarding workplace and home acceptance, self consciousness, adaptation, and overall satisfaction. Because of the nature of its technical performance and reliability, the VII-XII anastomosis is an important technique for the otolaryngologist to be familiar with. Cognizance of the functional and psychologic results with this procedure will ensure optimal (yet realistic) rehabilitation for this patient population.

Adaptation, Psychological↗
PubMed1986

Skull-base surgery: operative refinements.

Advances in microsurgical techniques, with the use of the laser and the ultrasonic suction aspirator, have paved the way for even more aggressive surgical approaches to large skull-base lesions, such as glomus tumors, adenocarcinomas of the temporal bone, and cranial nerve neuromas. Postoperative morbidity of multiple cranial nerve dysfunction has been aggravated in the past by cerebrospinal fluid leakage and/or gastro-intestinal dysfunction. At the Otology Group, P.C., in the course of dealing with more than 86 skull-base tumors, we have developed a standardized, multispecialty approach to such extensive skull-base lesions, including tracheotomy, gastrostomy, "ventriculoatrial" shunt placement, and rotated temporalis muscle flap closure. This article presents cases that illustrate the evolution of the current, "standard skull-base" operative procedure and the rationale for incorporation of the shunt and the muscle flap closure as operative refinements. Their beneficial effects upon postoperative morbidity are detailed.

Adolescent↗
PubMed1986

Perioperative evaluation and care of patients with lesions involving the skull base.

Within the past quarter of a century, contributions to the surgical literature have steadily reflected an increasing interest in the surgical extirpation of lesions involving the skull base. While optimistic reports demonstrate a variety of operative techniques and clinical experiences, there has been a paucity of discussion regarding the intraoperative and perioperative management of these complex cases. Cognizant of the fact that the care of these patients is of paramount importance, we herein review our rationale and practiced protocol for management of this unique patient population. The removal of lesions that also require the sacrifice of multiple cranial nerves results in significant postoperative morbidity. With the significant cardiopulmonary challenges attendant upon long procedures, these patients require constant multisystem Infection surveillance, wound care, cardiopulmonary support, fluid and nutritional monitoring, vocal and pharyngeal rehabilitation, along with psychological support, manifest in a complicated array of managerial decisions, require an organized approach to optimize patient care.

Adolescent↗
PubMed1986

A systematic approach to the surgical management of acoustic neuroma.

Contemporary otomicrosurgical techniques have made total removal of acoustic tumor with preservation of the seventh and sometimes the eighth cranial nerves possible. The four approaches currently used in acoustic tumor surgery are the middle cranial fossa, the translabyrinthine, the suboccipital, and the combined translabyrinthine-suboccipital. This review examines the surgical results in the removal of more than 600 acoustic tumors and outlines a rationale for the choice of approach. Tumor size on computed tomographic scan and auditory reserve establish the parameters used in planning the surgical procedure. The translabyrinthine exposure is used most frequently followed by the combined translabyrinthine-suboccipital. The middle fossa and suboccipital approaches are used when preservation of hearing is attempted. Total removal of tumor was accomplished in more than 99% of patients with a mortality rate of less than 1%. Anatomic preservation of the facial nerve, which is directly related to tumor size, was achieved in more than 80% of patients. Preservation of hearing is unlikely when the tumor is larger than 2 cm; anatomic preservation of the cochlear nerve was successful in 73% of hearing preservation procedures.

Adolescent↗
PubMed1985

Chlorambucil therapy in rheumatoid arthritis: clinical experience in 28 patients and literature review.

Our clinical experience in 28 patients receiving chlorambucil for rheumatoid arthritis (RA) and the reports on chlorambucil therapy are reviewed. Our study population and other reports generally represent patients with severe RA who had either failed to improve or developed significant toxicity during previous treatment with conventional slow acting anti-rheumatic drugs (SAARDs). Seventy-two percent of patients had a significant clinical improvement during chlorambucil therapy and reports of complete remission are given, although the incidence of remission is unknown. Hematologic complications are often reported, but appeared more frequently in our experience than previously reported. Hematologic toxicity required that chlorambucil be discontinued in the majority of our cases. Two deaths from suspected drug induced malignancies are reported. Although chlorambucil appears to be effective in the control of active RA, the potential for drug induced toxicity and malignancies may outweigh the benefit of continued use of this experimental therapy in RA.

Adult↗
PubMed1985

Sudden hearing loss and cerebellopontine angle tumors.

Lesions of the cerebellopontine angle may cause a sudden hearing loss. To illustrate and reaffirm the importance of a thorough neurotologic evaluation we performed a retrospective review of the audiologic and clinical data available on 506 patients with proven lesions of the cerebellopontine angle. Seventy-seven patients (15.2%) were found to have a history commensurate with sudden hearing loss. We reviewed the relevant audiologic data as well as the clinical circumstances of this select patient population.

Adult↗
PubMed1985

Open mastoid procedures: contemporary indications and surgical technique.

The history of the management of chronic ear disease with and without cholesteatoma is dominated by a canal wall down philosophy. The implication is that such an open procedure insures disease control and an uncomplicated future. In point of fact, problem canal wall down procedures can be fraught with as many serious complications as their more controversial canal wall up counterpart is alleged to propagate. Such problem cavities most commonly result from poor execution of basic technique. The objective of this paper is to identify what constitutes a problem cavity and to describe the authors' techniques to avoid such difficulties. A technique has evolved which not only eradicates disease, but which is self-cleansing and of minimal impact on the patient's lifestyle. The authors' experience with canal wall down procedures is reviewed.

Adolescent↗
PubMed1984

Diagnosis and management of catecholamine secreting glomus tumors.

The clinical and diagnostic features of catecholamine secreting glomus tumors are reviewed. Three cases are reported, including the first documented case of a dopamine secreting glomus jugulare tumor. Based on this experience, the authors have outlined the indications for selective venous catheterterization studies and for pharmacologic blockage in the management of these patients. In addition to routine urinary screening, a high index of clinical suspicion is needed to avoid the complications associated with catecholamine secreting tumors.

Adult↗
PubMed1984

A case of rheumatoid nodule formation within the central nervous system and review of the literature.

We describe nodule formation within the central nervous system (CNS) in a patient with seropositive rheumatoid arthritis (RA). Review of 13 previous reports of CNS rheumatoid nodule formation suggests that the clinical course is usually one of longstanding seropositive disease. Correlation of neurologic signs and symptoms with anatomic lesions has frequently been tenuous. We conclude that CNS nodules are a rare extraarticular feature of RA which, although often of uncertain clinical significance, should be considered as a possible etiology when neurologic dysfunction occurs in the RA patient.

Arthritis, Rheumatoid↗
PubMed1983

Ossicular chain reconstruction: the TORP and PORP in chronic ear disease.

The traditional objectives of tympanoplasty are infection control, closure of the ear by grafting techniques, and hearing rehabilitation via ossicular reconstruction. The multiplicity of contemporary prostheses and surgical options available would seem to underscore the magnitude of the ossicular reconstruction problem in the difficult chronic ear relative to all else. The success of stapedectomy has led to great expectations for all problems of ossicular reconstruction. The circumstances of the chronic ear is a milieu hostile in comparison and precludes any such comparison. Multiple sites of ossicular pathology, variations in mucosa health, inconsistent middle ear aeration and the overall complexity of the chronic ear present the otologist with a physiodynamic problem the solution of which is far from simplistic. The TORP and PORP have been enthusiastically endorsed in this regard, as a very suitable answer. Such enthusiasm, however, has been largely derived from data accumulated in the short term, often in less than a year's follow-up. This report reviews the authors' results in 141 patients in whom 86 TORPs and 55 PORPs were employed. For comparison, hearing data in 276 ears in which the fitted incus prosthesis, the authors' preferred reconstruction format, was used. Success for TORP reconstruction was assessed as air-bone gap closure to within 30 dB and for PORP, to within 20 dB. This was accomplished in 85% and 49% respectively. Extrusion rate, overall, was 10%. Relative advantages and disadvantages of the TORP and PORP are discussed and serve as a basis for the decision to continue to use this method of ossicular reconstruction. This data is put into perspective in acknowledging that the TORP and PORP are not the ultimate solution to this problem. When employed in combination with newer techniques in cartilage tympanoplasty, further improvement is expectant.

Chronic Disease↗