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Biomedical subjects

G R Barker

Publications and source records attributed to G R Barker.

At least 37 records · Page 2Linked to original sources
PubMed1988

Effect of the calcium entry blocker verapamil on renal ischemia.

The ability of the calcium entry blocker verapamil to ameliorate the effects of renal ischemia was studied in ten sheep. Postanesthesia, bilateral cutaneous ureterostomies were placed in each sheep to facilitate urine collection and analysis. Both kidneys were made ischemic for one hour by occluding each renal artery. However, immediately before occlusion of the right renal artery, 0.05 mg/kg of verapamil was injected into the artery. Comparison of urinary creatinine excretion and urine volume for 72 h after reversal of ischemia demonstrated that those kidneys pretreated with verapamil had greater functional preservation (p less than .05). In this study, verapamil appeared to provide protection against renal damage after an ischemic insult.

Acute Kidney Injury↗
PubMed1987

Applications of trigeminal somatosensory evoked potentials (TSEPs) in oral and maxillofacial surgery.

The initial results of trigeminal somatosensory evoked potentials (TSEPs) which were recorded in 17 patients, age range 16-64 years, presenting with established unilateral sensory impairment to the face or oral cavity, are described. Nerve potentials were evoked by stimulation of the normal healthy side and compared with those recorded from the side with disturbed sensation. The recorded waveforms allowed identification of a prominent sequence of events. Significant increases in the latencies compared to the events previously determined in normal subjects at 20, 30 and 39 msec. were found, and considered to be associated with clinical sensory impairment.

Adolescent↗
PubMed1987

Three-dimensional reformations of computed tomography in the assessment of facial trauma.

Three-dimensional (3D) computed tomography (CT) reformations were obtained in 15 patients presenting with facial injuries of differing severity. The 3D images were compared with standard radiographs and high resolution CT, including multiplanar reformations, and assessed under the headings of fracture detection, extent and displacement using a simple scoring system. 3D was valuable in severe trauma with multiple fractures, providing a clear demonstration of fraction extent and fragment displacement. 3D was much less useful in minor trauma in which little or no fragment displacement had occurred, and demonstrated fewer fractures overall than either radiography or CT in all categories of facial injury. When used as part of a high resolution CT examination 3D imaging can provide useful information to both radiologist and surgeon in cases of severe facial trauma.

Facial Injuries↗
PubMed1987

Superiority of intravesical immunotherapy with Corynebacterium parvum and Allium sativum in control of murine bladder cancer.

Intravesical immunotherapy with bacillus Calmette-Guerin (BCG), Corynebacterium parvum (CP), keyhole limpet hemocyanin (KLH), and an extract of Allium sativum (AS) was studied in mice transplanted intravesically with mouse bladder tumor cells (MBT-2). Female C3H/He mice were anesthetized with sodium pentobarbital. Two X 10(5) MBT-2 cells were delivered into the bladder transurethrally using a small catheter, immediately after the posterior wall of the bladder had been electrocauterized. Bladder tumor became palpable or demonstrable microscopically in two weeks. Immunotherapy with BCG (2 X 10(6) CFU), CP (250 micrograms), KLH (50 micrograms), or AS (25 mg) was administered directly into the bladder via urethral catheter on day 1, day 6, or days 1 and 6. On day 21 the bladders and spleens were excised and weighed, and the bladders were examined macroscopically and microscopically for evidence of tumor. The results of the study showed that two treatments given one and six days after tumor transplant yielded the lowest tumor incidence and that CP and AS appeared equally effective or even slightly more effective than BCG in this model. These results suggest that clinical evaluation of CP or AS may be worthwhile.

Adjuvants, Immunologic↗
PubMed1987

Trigeminal somatosensory evoked potentials. A review of the literature as applicable to oral dysaesthesias.

Oro-facial sensory impairment is a common event following third molar extractions, osteotomies and maxillo-facial trauma. Trigeminal somatosensory-evoked potentials (TSEPs) may offer an objective means of assessing neuronal function in such cases. TSEPs may be recorded non-invasively in man following peripheral stimulation of the trigeminal nerve, the principal nerve of oro-facial sensation. TSEP recording has gained popularity over the last decade and it is thus timely to review experimental methods and proven clinical applications in the light of recent interest in this technique within oral and maxillo-facial surgery.

Animals↗
PubMed1987

Normative studies of the TSEP. The basis of an objective sensory testing procedure in oral and maxillofacial surgery.

Disturbances of oro-facial sensation may frequently complicate dental surgical procedures, including the extraction of impacted third molars and osteotomies, and are often associated with fractures of the facial bones. The development and refinement of an objective measure of this clinical problem is highly desirable, particularly as it is increasingly being raised as a medico-legal issue. Evoked potential techniques have attracted considerable attention as a means of assessing the function and integrity of nervous pathways. An investigation of the trigeminal somatosensory evoked potential (TSEP) has been undertaken, in the hope of providing a safe, simple objective test of oro-facial sensibility that is acceptable to the patient. The 'normal' TSEP response has been standardised in 23 healthy volunteers, and the typical evoked waveform was found to be in line with the findings of other investigators. The TSEP waveform begins with a positive deflection at 20 ms (P20), followed by a negative deflection at 29 ms (N29) and then a second positive deflection at 37 ms (P37). In all cases, standard stimulation and recording procedures were followed. Stimulation of the maxillary or mandibular branches of the trigeminal nerve at the lip or the gingiva was employed. Evoked potentials were recorded at scalp loci overlying the oro-facial representation area of the post-central gyrus. Averaging and display of data was governed by microcomputer. A standardised method for recording trigeminal evoked responses was satisfactorily achieved and it is suggested that the technique may be useful in the clinical assessment of oro-facial sensory loss.

Adult↗
PubMed1987

Auditory tube function and audiogram changes following corrective orthognathic maxillary and mandibular surgery in cleft and non-cleft patients.

Orthognathic surgery is frequently undertaken to correct maxillary hypoplasia and mandibular deformity in both the cleft and non-cleft patient. These procedures lead to surgical disruption of the pterygoid fossa. Lying within this area is the auditory tube and the muscles of the soft palate. Hearing sensitivity testing methods, auditory tube function tests and middle ear pressure measurements show that in the early post-operative period the auditory tube is not functioning normally and that there is fluid collecting in the middle ear. For some patients these tests are still abnormal when repeated 6-8 weeks post-operatively and indicate that during the postoperative period auditory tube functioning tests may be required to prevent permanent hearing impairment.

Adolescent↗
PubMed1986

Intraosseous lipomas: clinical features of a mandibular case with possible aetiology.

There are few reported cases of intraosseous lipoma of the jaws in the literature. The exact nature of these lesions is debatable, but it is widely accepted that they represent true benign tumours. In this presentation discussion is centered on a case of a lipomatous lesion of the mandible and is the first to be reported in relation to a retained apex. The features for and against this lesion being of a neoplastic origin are discussed. The characteristic histopathological finding was the presence of only mature adipose fat cells.

Female↗
PubMed1986

Superiority of intralesional immunotherapy with Corynebacterium parvum and Allium sativum in control of murine transitional cell carcinoma.

Immunotherapy with bacillus Calmette-Guerin (BCG), Corynebacterium parvum (CP), keyhole limpet hemocyanin (KLH) and an extract of Allium sativum (AS) was studied in a transitional cell carcinoma (MBT-2) in mice. Comparison was made between intraperitoneal (IP) versus intralesional (IL) administration of these agents. C3H/He mice were transplanted subcutaneously in the hind limb with 5 X 10(4) tumor cells. After transplantation, mice were randomized into groups to receive either IP or IL treatments with BCG (2 X 10(6) CFU), CP (250 micrograms.), KLH (50 micrograms.) or AS (25 mg.). At weekly intervals the tumor volume was determined. To assess the local cellular events following these treatments, histopathological studies were performed 10 days after tumor transplant with tissues removed from the injected sites. IL route was much more effective than IP route in inhibiting tumor growth. CP and AS exhibited more significant therapeutic effect than BCG or KLH. No tumor developed in mice which received five IL treatments of CP or AS. The data indicate that CP or AS may serve as effective biological response modifiers in controlling transitional cell carcinoma. The study further emphasizes that route and frequency of administration are crucial variables determining efficacy of immunotherapy.

Animals↗
PubMed1986

Lymphocytic lymphoma of the oral cavity and skeletal myeloma.

A 50-year-old woman had a fleshy lesion in her right buccal maxillary sulcus. This was shown to be a lymphocytic lymphoma. Further investigation also revealed multiple myeloma. The presence of 2 separate disease processes, which may have a common origin in the cells of the lymphoreticular system, is unusual.

Female↗
PubMed1985

Renal preservation following severe ischemia and prophylactic calcium channel blockade.

The ability of the calcium channel blocker verapamil to prevent renal ischemic damage was assessed in a randomized double blind study of 41 rats. Study animals received either intravenous verapamil or placebo prior to renal pedicle occlusion and contralateral nephrectomy. Rats receiving verapamil pretreatment demonstrated significantly greater functional preservation 48 hours after ischemia (p less than 0.005) and exhibited better overall survival rates. In this study verapamil provided protection against renal damage following ischemia.

Animals↗
PubMed1984

Unifocal lymphomas of the oral cavity.

The diagnosis of unifocal oral lymphomas is not easy and yet, a retrospective review of the malignancies diagnosed by the University of Birmingham Department of Oral Pathology, indicates that lymphoma is the third most commonly diagnosed malignant lesion in the oral cavity. In a separate study of all the cases of unifocal oral lymphomas which are recorded in the Birmingham and West Midland Cancer Registry for the period 1957-1976, lymphomas were found in the cheek, the lip, the tongue, the alveolus, the hard palate and soft palate, the gingival and oral mucosa overlying the buccal sulcus and in the salivary and mucous glands. The survival rates of patients with lymphomas underline the fact that the prognosis falls rapidly from the early stages where the lymphoma lesion is relatively small, single and isolated, to the later stage where there is also involvement of the associated lymph nodes.

Adolescent↗