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Biomedical subjects

J H Robertson

Publications and source records attributed to J H Robertson.

At least 19 recordsLinked to original sources
PubMed2000

Meningiomas of the cerebellopontine angle.

BACKGROUND: Meningiomas of the cerebellopontine angle (CPA), although uniform in location, are diverse with regard to the site of dural origin and displacement of neurovascular structures. A study of patients with CPA meningiomas was undertaken to gain more information regarding the relationship between site of dural attachment, clinical presentation, operative approach, and outcome. METHODS: In this report, we retrospectively review 40 patients with CPA meningiomas managed surgically. RESULTS: Common clinical presentations were hearing loss, unsteadiness, and dysequilibrium. Findings upon physical examination included hearing loss (73%), cerebellar signs (32%), trigeminal neuropathy (16%), and facial nerve dysfunction (16%). The most common site of dural origin was the petrous ridge (anterior to the IAC [26%], posterior [21%], superior [18%], and inferior [16%]). Less common sites of dural origin included the tentorium (31%), the clivus (15%), the IAC (10%), and the jugular foramen (8%). Site of dural origin determined the direction of displacement of the facial/vestibulocochlear nerve bundle. The most common microsurgical complication was facial nerve dysfunction (30%). Gross total resection was achieved in 82% of cases, whereas 18% underwent subtotal resection. Two patients died. Follow-up ranged from three months to 13 years with three recurrences. CONCLUSIONS: CPA meningiomas displace the seventh and eighth cranial nerves in various directions depending on the site of dural origin. Total surgical excision can be accomplished in the majority of cases with acceptable morbidity.

Adult↗
PubMed1997

Image-interactive orientation in the middle cranial fossa approach to the internal auditory canal: an experimental study.

Approaches through the middle cranial fossa directed at reaching the internal auditory canal (IAC) invariably employ exposure of the geniculate ganglion, the superior semicircular canal (SSC) or the epitympanum. This involves risk to the facial nerve and hearing apparatus. To minimize this risk, we conducted a laboratory study on 9 cadaver temporal bones by using an image-interactive guidance system (StealthStation) to provide topographic orientation in the middle fossa approach. Surface anatomic fiducials such as the umbo of the tympanic membrane, Henle's spine, the root of the zygoma and various sutures were used as fiducials for registration of CT-images of the temporal bone. Accurate localization of the IAC was achieved in every specimen. Mean target localization error varied from 1.20 to 1.38 mm for critical structures in the temporal bone such as the apex of the cochlea, crus commune, ampula of the SSC and facial hiatus. Our results suggest that frameless stereotaxy may be used as an alternative to current methods in localizing the IAC in patients with small vestibular schwannomas or intractable vertigo undergoing middle fossa surgery.

Cadaver↗
PubMed1997

Use of cranial surface anatomic fiducials for interactive image-guided navigation in the temporal bone: a cadaveric study.

OBJECTIVE: Because of the intricate anatomy of the temporal bone, we examined the feasibility and reliability of cranial surface anatomic fiducials to register computed tomographic images of the temporal bone by using a frameless image-guided system. METHODS: One-millimeter thick computed tomographic slices and the smallest possible field of view were used to register 10 dry and 10 fresh temporal bones from cadavers. The fiducials used for registration included the umbo of the tympanic membrane, emissary foramina, the asterion, various sutures, the tip of the mastoid process, and Henle's spine. RESULTS: Mean initial fiducial registration error ranged from 0.6 to 0.7 mm, and was reduced to 0.5 and 0.4 mm for the dry cranial and cadaveric studies, respectively, by eliminating or reregistering inexact fiducials. Mean target localization error ranged from 0.91 to 2.44 mm for superficial structures of the temporal bone in the dry cranial specimens and from 0.71 to 1.52 mm for deep structures such as the facial nerve, semicircular canals and ossicles in the cadaveric study. CONCLUSION: Interactive image-guided navigation in the temporal bone is possible with registration of cranial surface anatomic fiducials. It may be useful to the neurosurgeon and otologist in identifying critical anatomic structures of the temporal bone encountered during the translabyrinthine, retrolabyrinthine presigmoid, and suboccipital approaches.

Cephalometry↗
PubMed1996

Cholesterol granulomas of the petrous apex: combined neurosurgical and otological management.

Cholesterol granulomas of the head are relatively rare. Isolated lesions of the cerebellopontine angle are even more uncommon. In this report, 17 cases of petrous apex cholesterol granulomas are presented and management is discussed. Symptoms at presentation included dizziness (14 patients), pressure (nine patients), tinnitus (eight patients), hearing loss (eight patients), otalgia (six patients), headache (six patients), nausea (three patients), drainage from ear (two patients), facial pain (two patients), seizure (two patients), lightheadedness (one patient), hemifacial spasm (one patient), and facial numbness (one patient). Six cases were managed without surgery and 11 patients underwent operative procedures. The approaches used included the infralabyrinthine (eight patients), transcanal-infracochlear (two patients), and translabyrinthine (one patient). The mean follow-up period for all cases was 29.5 months. Of those patients managed without surgery, symptoms improved in all except one, whose tinnitus was slightly worse. Of surgically treated patients, symptoms improved or remained the same except in one with worsened dizziness. There were nine patients with hearing present presurgery and seven whose hearing was preserved postsurgery. The authors present a case that was managed at another center where an attempt at surgical resection through a subtemporal middle fossa approach was unsuccessful. This lesion was successfully treated using an infralabyrinthine approach with drainage into the mastoid cavity. Cholesterol granulomas of the petrous apex can be managed without surgery when symptoms are stable or improve. Otherwise, a transmastoid extradural approach with simple drainage into the mastoid sinus or middle ear produces symptomatic improvement with low morbidity. Resection of petrous apex cholesterol granulomas is not necessary.

Adolescent↗
PubMed1996

Synthesis and biological evaluation of a series of tyrphostins containing nitrothiophene moieties as possible epidermal growth factor receptor tyrosine kinase inhibitors.

A series of 36 nitrothiophene tyrphostins were synthesized, 32 of which were novel structures. Their ability to inhibit the epidermal growth factor (EGF) receptor tyrosine kinase was assessed in a cell-free assay. Compounds containing a dinitrile, 2-aminoethene-1, 1-dinitrile or a thioamide group were good inhibitors of the receptor tyrosine kinase. Although anti-proliferative and cytotoxic activity was seen, no evidence of inhibition of EGF receptor autophosphorylation in intact cells was observed. The compounds showed no preferential inhibition of EGF-dependent proliferation of fibroblasts transfected with the EGF receptor. Furthermore, in a panel of squamous cell carcinoma cell lines with varying levels of EGF receptor expression, there was no selective cell kill of lines with the highest EGF receptor expression. The 2-nitro-5-substituted-thiophenes and the 2-nitro-3-substituted-thiophenes showed reduction potentials falling within the range likely to be reduced by cellular reducing agents, while the 2-nitro-4-substituted-thiophenes and 4-nitro-2-substituted-thiophenes did not. Compounds from the 2-nitro-5-substituted-thiophene series were shown to induce DNA damage, while no evidence of DNA damage was demonstrated with compounds from the 2-nitro-4-substituted-thiophene series. The 2-nitro-5-substituted-thiophene compound 4 showed significant tumour-type selectivity in the US National Cancer Institute human tumour cell line panel. The leukaemia cell lines were particularly sensitive to the compound, as were the majority of the colon cancer, melanoma and breast cancer cell lines, while the central nervous system-derived lines and the non-small cell lung cancer lines were particularly resistant. Further work is required to determine the precise mechanisms involved in these effects.

Antineoplastic Agents↗
PubMed1994

Cytological changes preceding cervical cancer.

Cervical smears were reviewed from 62 women who developed squamous carcinoma of the cervix up to 18 years later. The findings indicate that the prevention of cervical cancer by screening depends very largely on the detection of severe dyskaryosis. In this series there was no evidence that mild dyskaryosis was a forerunner of invasive disease. Cytology during the evolution of squamous carcinoma is not characterised by a dyskaryosis which progressively increases in severity. Instead the findings support new concepts that cervical cancer generally arises from an aggressive CIN 3 lesion widely present in the cervix, and in our series, established years before invasion occurs. It would be more useful to report cytology as showing either a low or high grade abnormality rather than distinguishing between different degrees of dyskaryosis.

Adult↗
PubMed1993

Negative cytology preceding cervical cancer: causes and prevention.

AIM: To assess the validity of negative cervical smear reports in women who subsequently developed cervical cancer; and to determine means of improving the screening process. METHODS: One hundred and forty cervical smears, initially reported as negative from 103 women, and taken up to 12 years before diagnosis of cervical cancer, were reviewed. RESULTS: Ninety two smears contained dyskaryotic cells. Analysis showed that these smears formed several well defined patterns. False negative reports were likely to occur if fragments of neoplastic tissue rather than dissociated dyskaryotic cells were present or if the smear contained few dyskaryotic cells. Screening fatigue appeared to be a factor in others. It was also considered important that smears contained cells from the endocervix. These were deficient in 64% of the 47 smears confirmed as negative on review and in 69% of smears containing only a few dyskaryotic cells. CONCLUSIONS: Current methods of quality assurance will not remedy these defects in the screening process. It is the responsibility of laboratories to identify sources of poor smears and liaise with smear takers to ensure an improvement in quality. Assessment of the quality of smears received by a laboratory should become an important part of audit. Staff training should place more emphasis on the interpretation of "microbiopsies". The adoption of a quick scanning technique before conventional screening would probably also substantially reduce false negative results.

Adenocarcinoma↗
PubMed1993

Myeloma--results of treatment 1986-1990.

Sixty-nine patients with multiple myeloma diagnosed during a five year period at the Belfast City Hospital were followed until death or for a minimum of one year in a retrospective study of survival. Although the patients were unselected, survival data was found to be similar to results from trials in which patient selection had occurred. Overall median survival was thirty-two months. Median survival fell with advancing disease and was 47, 27 and 18 months for Durie-Salmon stages I, II and III respectively. Those patients presenting with a platelet count of < 100 x 10(9)/1 had a median survival of eight months in contrast to those with a platelet count > 100 x 10(9)/1 whose median survival was 36 months. Patients presenting in renal failure had a shorter median survival of 28 months compared to 46 months for those with normal renal function.

Adult↗
PubMed1992

The changing pattern of cervical cancer in Northern Ireland 1965-1989.

There was a change in pattern of an increased prevalence of cervical cancer in Northern Ireland from 1965 to 1989, characterised by an increased incidence in women under 40 years. These changes occurred despite special screening of younger women, although the screening programme has probably prevented an even greater increase in incidence of the disease. To reduce the incidence of cervical cancer, not only systematic screening but also cervical smears at more frequent intervals would be required.

Adenocarcinoma↗
PubMed1990

The extended maxillotomy and subtotal maxillectomy for excision of skull base tumors.

An approach to tumors of the middle compartment of the skull base is described with three case reports. It is accomplished by extending the subtotal maxillectomy or maxillotomy to include removal of a part of the malar bone, coronoid process of the mandible, nasal turbinates, ethmoid and sphenoid sinuses, posterior nasal septum, and pterygoid plates. Extension of the incision through the anterior tonsillar pillar and lateral pharyngeal wall into the retropharyngeal space will assist to expose the craniocervical region from the sphenoid roof to the fifth cervical vertebra and the skull base between each eustachian tube and carotid canal. The function of the trigeminal, facial, and hypoglossal nerves, hearing, and nasal airway are preserved without mastoidectomy. A temporalis muscle flap closes the defect. Dysphagia and aspiration are not handicaps.

Adult↗
PubMed1989

Immunoglobulin light chains in common acute lymphoblastic leukaemia.

A single immunoglobulin light chain lambda was identified in the blast cells of two out of 12 patients with common acute lymphoblastic leukaemia (C-ALL) using the alkaline phosphatase/anti-alkaline phosphatase (APAAP) technique. Inhibition at the cell surface proved that the reaction was a genuine anti-lambda reaction. Immunoglobulin mu chain was not identified in these patients. Results of immunoglobulin typing in 103 patients with B chronic lymphocytic leukaemia (B-CLL) are cited to show the increased sensitivity of the APAAP technique as compared to the indirect immunoperoxidase technique for cellular immunoglobulin identification.

Female↗
PubMed1988

Risk of cervical cancer associated with mild dyskaryosis.

In a survey of 1781 patients who had mild dyskaryosis in a cervical smear taken between 1965 and 1984 invasive cancer occurred in 10 women. In four cancer was diagnosed soon after presentation, and in three it developed some years after default from follow up. Invasion occurred in one patient during cytological surveillance and in a further two after referral for colposcopic supervision. A poor correlation was found between a single cervical smear showing mild dyskaryosis and biopsy results. This was, however, improved by a series of smears. During initial surveillance cervical smear results reverted to normal in 46% of our patients within two years. During longer term follow up none of these patients developed invasive cancer, and life table analysis showed that three quarters had not relapsed after 14 years. We also found no evidence to suggest that preinvasive disease is more rapidly progressive in younger women. Our results indicate that cytological surveillance is acceptably safe provided that biopsy is advised if dyskaryosis persists.

Actuarial Analysis↗
PubMed1988

The effect of transportation between the recovery room and intensive care unit on postoperative acoustic tumor patients.

Cardiovascular changes have been noted to occur during movement from the operating room or recovery room (RR) to the intensive care unit (ICU). This study examined blood pressure changes and related variables during transport from the RR to the ICU in 135 postoperative acoustic tumor patients. Although there was no significant change in blood pressure values from the RR to the ICU, patients with pre-existing hypertension and elevated RR blood pressures were noted to have an increased frequency of postoperative complications. In addition, a relationship was noted between administration of halothane and frequency of postoperative complications. Results highlight the need for nurses not only to monitor, but also closely control postoperative blood pressure in this population.

Blood Pressure↗
PubMed1987

Risk of recurrence after treatment of severe intraepithelial neoplasia of the cervix. A follow-up of 896 patients.

Eight hundred and ninety-six patients were followed up cytologically for up to 21 years following treatment for a CIN III lesion of the cervix. The recurrence rate (8.8%) was lower after hysterectomy than after treatment which preserved the cervix (23%). Long-term yearly follow-up is not required as all recurrences were detected by annual smears for a seven-year period after treatment in both groups. It is important to keep patients under cytological review following hysterectomy because of the appreciable recurrence rate and also evidence that intraepithelial lesions of the vaginal vault behave in an aggressive fashion.

Carcinoma in Situ↗