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Biomedical subjects

D A Ross

Publications and source records attributed to D A Ross.

At least 109 records · Page 6Linked to original sources
PubMed1997

Cranial nerve defects in congenital facial palsy.

METHODS: Cranial nerve defects were enumerated in 29 children with congenital facial palsy presenting for reanimation via chart review with a view to determining unaffected donor nerves. The literature was searched via Medline to reveal 186 additional case reports that were complete enough in their description to allow assessment of cranial nerve defects. RESULTS: The group presenting for reanimation comprised 24 females and 5 males. All of the males had unilateral isolated facial nerve paralysis. Of the females, 9 had isolated unilateral palsy and 14 had bilateral palsy, and half of these were isolated. Six had bilateral abducens nerve palsy, fulfilling the original definition of Möbius syndrome. Of these, 3 had a right-sided hypoglossal weakness, one had a bilateral oculomotor palsy, and one had a bilateral trochlear palsy. One girl had bilateral facial and auditory involvement. The literature review revealed a group that was 60% male, with 85% having bilateral facial palsy. Abducens palsy was present in 68%, glossopharyngeal in 28%, hypoglossal in 26%, and oculomotor in 20%. The group was very heterogeneous in many ways. CONCLUSIONS: There are many theories of pathogenesis of this syndrome. Isolated facial palsy is in concordance with previous findings of nerve lesions within the temporal bone. Multiple cranial nerve defects are more likely to have brainstem lesions, related to prenatal ischemic events. The cranial nerve least likely to be involved was the accessory nerve, suggesting that this may be a reliable donor for reanimation procedures.

Child↗
PubMed1997

Flow cytometric analysis of p53 oncoprotein expression in cutaneous melanoma.

BACKGROUND: Mutation of the p53 tumour suppressor gene is thought to represent a significant step in the development of over half of all human cancers. Qualitative investigations of p53 protein in cutaneous melanoma suggest that overexpression is more common than in other tumours. This study analysed p53 protein expression using flow cytometry as a quantitative assay. METHODS: Expression of p53 protein was assayed in ten benign melanocytic naevi (BMN) and 50 surgically excised ethanol-fixed melanomas. Nuclei were stained for the p53 protein with Pab1801 and analysed using flow cytometry. Protein expression was further correlated with clinicopathological parameters. RESULTS: None of the BMN was immunopositive for p53. Forty-one of the 50 melanomas stained positively. The overall median positivity for p53 in primary melanoma was 12.8 per cent compared with 22.5 per cent in metastatic disease. No association was found between p53 expression and Breslow thickness or presence of nodal and skin metastases. Overexpression of p53 was associated with ulceration, mitotic figures and lymphocytic infiltration, and there was a striking increase of p53 expression with age. Expression of p53 was inversely correlated with disease-free interval. CONCLUSION: Although overexpression of p53 is common in melanoma, there was no association with major clinical parameters such as Breslow thickness and overall survival. The association found between p53 and other clinicopathological features suggests that the tumour suppressor gene does play a role in the evolution of melanoma.

Adult↗
PubMed1997

A comparison of the predictive power for survival in gliomas provided by MIB-1, bromodeoxyuridine and proliferating cell nuclear antigen with histopathologic and clinical parameters.

The purpose of this prospective study of 65 patients was to compare side-by-side the predictive power for survival of (a) MIB-1, (b) bromodeoxyuridine (BUDR), and (c) proliferating cell nuclear antigen (PCNA). They were compared (a) with each other, (b) with several clinical predictors, and (c) with histopathologic grade under actual clinical biopsy conditions in a study of 1993 World Health Organization (WHO) grade II to IV adult supratentorial gliomas. There was a strong positive relationship between MIB-1 and BUDR by Spearman Rank correlation. In univariate analysis, MIB-1 (logrank p = 0.06) was more predictive of survival than BUDR or PCNA. Longer survivors were distinguished from others by the lowest MIB-1 labeling indices (LI < or = 2.5%) better than by the lowest histopathologic grade. However, histopathologic grades were highly predictive among the entire group (logrank p < 0.0001). Young age (p < 0.0001) and high Karnofsky performance status (p < 0.0001) were the clinical factors most predictive of longer survival. Female gender correlated with longer survival (logrank p = 0.02). In multivariate Cox proportional hazards models, age, Karnofsky performance status, and histopathologic grading remained statistically significant after full reduction of the model. We conclude that Ki-67 measured by MIB-1 monoclonal antibody was superior to other markers of proliferation. When all factors are considered simultaneously over all 3 grades of malignancy, greatest predictive power resides in histopathologic grade and clinical variables. MIB-1 is expected to be most important in cases where clinical or histopathologic factors are ambiguous or where they cannot be fully assessed.

Adult↗
PubMed1996

Is prevalence of diarrhea a better predictor of subsequent mortality and weight gain than diarrhea incidence?

A number of different outcome measures have been proposed for use in prospective studies of morbidity associated with childhood diarrhea. These include the number of episodes experienced by each child over a defined period (a measure of incidence) and the number of days of diarrhea divided by the total number of days of observation for each child (a measure denoted "longitudinal prevalence"). The authors examined data from Ghana to determine which of these measures is more strongly associated with weight gain over a 4-month period and subsequent mortality. Both diarrhea incidence and longitudinal prevalence were associated with weight gain in children aged 6-23 months, but a statistically stronger association was observed with longitudinal prevalence (likelihood ratio statistic 28.95 on 1 degree of freedom against 19.70 for incidence). Neither measure was associated with weight gain in younger or older children. Longitudinal prevalence, but not incidence, was strongly associated with subsequent mortality (p = 0.002 for longitudinal prevalence; p = 0.557 for incidence). Although many epidemiologic studies of diarrhea focus on incidence, these data suggest that longitudinal prevalence is more strongly predictive of long-term health outcome. The authors conclude that longitudinal prevalence merits greater attention as a measure of outcome in diarrhea studies.

Child, Preschool↗
PubMed1996

Loss of heterozygosity of chromosome 10p in human gliomas.

Molecular loss of heterozygosity studies on human gliomas have shown several regions on chromosome 10 frequently deleted in higher grade tumors, suggesting that chromosome 10 may contain several tumor suppressor genes. We assessed loss of heterozygosity with microsatellite markers in 20 gliomas, consisting of various grades and containing two chromosome 10 copies. The locus that exhibited the most loss (69%) was the region bordered by D10S249 and D10S558 and inclusive of D10S594, with a linkage distance of 3 cM. This region was noted to be deleted in various grades of tumor, including low- and high-grade tumors. These results suggest that chromosome region 10p15 is involved in human gliomas of diverse grades and that this region may harbor genes important in the development of and progression to the malignant phenotype.

Astrocytoma↗
PubMed1996

C-myc oncogene expression in human melanoma and its relationship with tumour antigenicity.

Melanoma produces specific tumour antigens which are capable of eliciting an immune response. However, this tumour evades the immune system, in part, by downregulation of class I HLA antigens on the cell surface, which are required for T cell recognition. It has been suggested that the oncogene c-myc may have a role in effecting this change in vitro, however, the relationship between oncoprotein level and tumour antigenicity has not been established in human tumours. This study measured c-myc oncoprotein in 94 melanoma specimens (46 primary tumours and 48 regional metastases) using flow cytometry and evaluated class I HLA expression with immunohistochemistry. C-myc expression was found in 91 tumours (96%) with higher expression in metastases than primary melanomas (P<0.005). Class I HLA expression was found to show great variation although metastases showed less antigenicity than primary tumours (P<0.01). Analysis of the relationship between these two parameters revealed a highly significant correlation in both primary (P<0.01) and metastatic disease (P<0.01), with high oncoprotein being associated with down regulation of cell surface antigens. Knowledge of the control of tumour antigenicity is likely to provide an objective platform for the development of new strategies for immunotherapy.

Antigens, Neoplasm↗
PubMed1996

Drinking water sources, mortality and diarrhoea morbidity among young children in northern Ghana.

In the Upper East Region of Ghana, considerable resources have been invested in the provision of boreholes. As part of the Ghana Vitamin A Supplementation Trials' Survival Study which was carried out in one of the districts of the Upper East Region between January 1989 and December 1991, data were collected over a period of one calendar year on the drinking water sources used by approximately 13,000 mothers/guardians of over 20,000 children and on the morbidity and mortality experiences of these children. These data were used to describe seasonal and geographical variations in drinking water sources; to look for other predictors of water source use; and to establish whether the drinking water source was associated with the risk of child death or the period prevalence of diarrhoea among young children. Boreholes were used as the main source of drinking water by about 60-70% of respondents. They were used slightly more frequently in the dry season. In the rainy season, the use increased of more traditional sources such as rainwater or holes dug in stream beds. The use of boreholes was greatest in the northern zone of the study area and was more common in those who had had some formal education and were of higher socioeconomic status. Some association was found between reported drinking water source and diarrhoeal morbidity, although this association appeared to be seasonal. No significant association was found between drinking water source and child mortality.

Child↗
PubMed1996

Effect of vitamin A supplementation on the growth of young children in northern Ghana.

The effect of prophylactic vitamin A supplementation on child growth was studies in two randomized, placebo-controlled trials carried out in adjacent areas of northern Ghana between 1989 and 1991. In the Health Study, the midupper arm circumference (MUAC) and weight of the approximately 1500 children (aged 6-59 mo) in the trial were measured every 4 wk for up to 52 wk. In addition, MUAC, weight, and height were measured at each of the four potential vitamin A or placebo dosing times, which were at 4-mo intervals. In the Survival Study, MUAC and weight were measured at 4-mo intervals at each of seven dosing rounds in the approximately 15 000 children currently in the trial. Overall, there were > 90 000 observations of weight and MUAC in > 25 000 children, and 3347 observations of length/height in 1546 children. Within each study, the mean monthly weight, MUAC, and gains in length/height in each treatment group were compared by using multilevel modeling. There were no significant differences in either MUAC or gains in length/height. The only significant difference in weight gain was in the Survival Study: children in the vitamin A-supplemented group who were > or = 36 mo of age had a mean weight gain that was 3 g lower per month (95% CI: 0.4, 5.0, P = 0.02) than that in the placebo group; a difference that was unlikely to be functionally important in this age group. Vitamin A supplementation did not lead to any increased growth in this population of young children, in whom supplementation reduced mortality and severe morbidity substantially.

Anthropometry↗
PubMed1996

The extended lateral arm free flap for head and neck reconstruction: the Yale experience.

The lateral arm free flap (LAFF) has been chosen by some head and neck reconstructive microsurgeons to be their fasciocutaneous free flap of choice. The qualities of this flap have been suggested to include its consistent vascular anatomy, its thin and pliable nature, and its reinnervation capabilities, as well as its low donor site morbidity and ease of closure. During the past year we have performed 14 head and neck reconstructions using the extended LAFF (ELAFF). We present our indications for its use and review its shortcomings. Although the ELAFF does have its limitations, including variability in its flap thickness and donor vessel size, it unquestionably is an important flap in head and neck reconstruction and is our flap of choice for soft tissue reconstruction.

Adult↗
PubMed1996

Stereotactic microsurgical craniotomy for the treatment of third ventricular colloid cysts.

The treatment of colloid cysts remains controversial. This article reports on 18 patients with colloid cysts of the third ventricle who presented to the University of Michigan between January 1990 and June 1995. Two patients had conventional transcortical-transventricular approaches; the remaining 16 patients underwent a stereotactic modification of the transcortical approach, using a specially designed cylindrical retractor, for the resection of their colloid cysts. Minor morbidity and no mortality have been associated with this technique. There have been no instances of recurrence during the period of this report. The mean operative time for the two conventional craniotomies was 233 minutes, compared with 129 minutes for the stereotactic craniotomies. Our technique allows for a limited craniotomy and limited cortical disruption. It is not dependent on ventricular size. Localization of the colloid cyst is trivial because of modern stereotactic technology, and all standard microsurgical techniques can be used. The retractor is readily adaptable to any Leksell system. This technique shortens operative time, compared with conventional craniotomy, and allows for definitive treatment of the lesion.

Adolescent↗
PubMed1996

Use of the extreme lateral approach in the surgical treatment of an intradural ventral cervical spinal cord vascular malformation: technical case report.

Vascular malformations on the ventral aspect of the spinal cord are difficult to access surgically. Recently, selected lesions have been treated with endovascular embolization. However, embolization using currently approved agents may not be permanently effective, and recanalization rates range from 25 to 83% in the literature. Additionally, many of these lesions are not amenable to endovascular treatment because of the inadequate diameter, tortuosity, or lack of collateral flow of the anterior spinal artery from which the feeding arteries arise. Surgical approaches to these lesions have been posterolateral or anterior. The posterolateral approach requires division of the dentate ligaments and occasionally the adjacent nerve root and then rotation of the cord itself to allow visualization of the lesion. The anterior approach involves a multilevel corpectomy requiring subsequent bone grafting and stabilization. Certain lesions are not readily approachable by either method. We describe the use of the extreme lateral approach to successfully access and obliterate a Type IVa perimedullary fistula located adjacent to the midline ventrally at the C1-C2 level in a 72-year-old woman who had suffered a subarachnoid hemorrhage. The extreme lateral approach was originally designed to access neoplasms located ventral to the cord and brain stem; as a result of the posterior displacement of the spinal cord by the neoplasm, intraoperative visualization is improved. No posterior displacement was present with this malformation. Even without such cord displacement, the extreme lateral approach allowed excellent visualization of and access to the arteriovenous fistula, preserved important anatomic structures, and required essentially no rotation or compression of the spinal cord to successfully obliterate the lesion.

Aged↗
PubMed1996

Intracerebral depth electrode monitoring in partial epilepsy: the morbidity and efficacy of placement using magnetic resonance image-guided stereotactic surgery.

OBJECTIVE: To determine the indications for, efficacy of, and safety of depth electrode placement using magnetic resonance imaging (MRI)-guided stereotactic surgery in patients with intractable epilepsy. METHODS: We analyzed retrospectively the results of depth electrode usage in 50 consecutive patients at the University of Michigan Hospitals studied in the years 1991 through 1994, using MRI-guided stereotactic implantation, in conjunction with simultaneous subdural strip electrode recordings. RESULTS: There were no deaths, no infections, and no new neurological deficits. One small subdural hematoma adjacent to a subdural strip electrode was evacuated to prevent interference with ictal recording. Two cylindrical subdural electrodes were found to be intraparenchymal, as revealed by postoperative MRI, and were removed. One patient was unintentionally left alone briefly, and he pulled out the electrodes while confused postictally, requiring a subsequent operation for replacement. Ictal onset zones were successfully localized in 47 patients. CONCLUSION: We have found intracerebral electrode placement to be as safe as subdural strip electrode placement and have found combined depth and strip electrode monitoring to be highly effective in localizing the onset zones of complex partial seizures. Intracranial monitoring was particularly useful in the detection of a single ictal onset zone in the absence of neuroimaging abnormality and in the definitive diagnosis of bilateral independent ictal onset zones in the temporal lobe epilepsy syndrome. The specific technical aspects of the procedure that contribute to a successful outcome are reviewed. A comparison with earlier reported series suggests that MRI-guided stereotaxy and pial inspection may reduce complications of depth electrode placement.

Brain Mapping↗
PubMed1996

Is pharyngoplasty a risk in velocardiofacial syndrome? An assessment of medially displaced carotid arteries.

The association of medially positioned internal carotid arteries and velocardiofacial (Shprintzen) syndrome was first made in 1987. This is also the most common syndrome associated with facial clefting. The potentially dangerous implications in children with this syndrome requiring pharyngoplasty for velopharyngeal incompetence and stigmatized hypernasal speech involve potential damage to these vessels. This three-part study was undertaken to analyze this anatomic variant. First, a group of 25 children with velocardiofacial syndrome, velopharyngeal incompetence, and obvious posterior pharyngeal pulsations seen on nasendoscopy was studied by CT angiography to determine the degree of this abnormal vascular pattern. This technique, together with three-dimensional reconstructions, made it possible to determine the precise location of these abnormally positioned vessels. Second, our routine superiorly based pharyngeal flap was measured by lateral cervical x-ray to show the distal tip of the flap. The variance was minimal and demonstrated the tip of most flaps to be at the disk between the C2 and C3 vertebrae. By correlating this information with the CT angiography, the risk of surgery can be determined on strict anatomic grounds, allowing customized flap design in some unilateral cases. In this series of children, routine superiorly based pharyngoplasty would be safe in 52 percent, while in 28 percent a pharyngeal flap would be safe if custom designed, and in the remaining 20 percent surgery should not be attempted because the risk of damage to the carotid arteries is too great. Third, in a double-blind study, velocardiofacial children with obvious pulsations seen on nasendoscopy were grouped with other children with palatal dysfunction. When only endoral examination was performed by plastic surgeons and plastic surgical residents, no vascular pulsations were ever seen. This indicates another important role of nasendoscopy in the preoperative assessment of children for palatopharyngoplasty.

Carotid Arteries↗
PubMed1996

DNA testing in familial hypertrophic cardiomyopathy: clinical and laboratory implications.

Counselling and clinical assessment in familial hypertrophic cardiomyopathy (FHC) is difficult, particularly in the young, since echocardiographic and ECG changes may not be diagnostic and clinical severity can vary. From 1990, when the beta-cardiac myosin heavy chain gene was implicated in the aetiology of FHC, considerable information about the molecular genetics of this disorder has emerged. However, an important question facing health professionals is the practical significance of DNA testing in FHC. The present study describes a DNA-based approach to screening for five commonly reported mutations involving the beta-cardiac myosin heavy chain gene. Approximately 11% of randomly selected families had an abnormality detected.

Cardiomyopathy, Hypertrophic↗
PubMed1996

Endovascular therapy for the carotid blowout syndrome in head and neck surgical patients: diagnostic and managerial considerations.

PURPOSE: To review our institution's recent experience with patients with carotid blowout syndrome who were referred for emergency diagnostic angiography and endovascular therapy. METHODS: Eighteen consecutive patients who had had surgery for cancer of the head and neck and in whom carotid blowout syndrome had occurred were referred to our service in accordance with a standardized protocol. RESULTS: Twenty-three angiographic pathoetiologic conditions were diagnosed in the 18 patients; the majority of these were pseudoaneurysms involving various segments of the carotid system. Multiple lesions were detected in five patients. Most patients were treated by means of permanent balloon occlusion; in 8 patients with either multiple lesions or impending rupture requiring flap reconstruction, a composite permanent balloon occlusion of the affected carotid system was performed. Hyperacute hemorrhages were arrested in all cases. Hemorrhages reoccurred in 2 cases, and in 2 patients who had permanent balloon occlusion of the internal carotid artery, transient ischemic attacks occurred, which appeared to be related to temporary collateral reserve failure. No permanent neurologic complications ensued. CONCLUSION: Our recent experience with carotid blowout syndrome suggests that this clinical diagnosis represents a heterogeneous group of angiographic pathoetiologies that the physician should evaluate carefully before proceeding with endovascular therapy. Specific endovascular approaches depend on the pathoetiologic mechanism of active or impending hemorrhage and the urgency with which intervention is required.

Adult↗
PubMed1996

Improving the early detection of malignant melanoma.

The early detection of cutaneous melanoma is known to be associated with reduced mortality. In order to improve early detection of suspicious skin lesions a Pigmented Lesion Clinic (PLC) was set up at Mount Vernon Hospital in January 1993. Its aims were to provide a rapid method of expert assessment and treatment for malignant skin tumours as well as reassurance for patients with benign lesions. In the first 2 years, 1779 new patients were seen and 674 lesions excised, of which 18% were malignant. Comparison of the Breslow thicknesses of melanomas diagnosed via the PLC revealed a significant shift towards thinner early tumours when compared with the two previous years (chi 2 = 12.8, P < 0.01) and during the same time period via normal routes of referral (chi 2 = 8.68, P < 0.02). The running of such a service and its hidden benefits are discussed.

England↗
PubMed1996

Sentinel transoral hemorrhage from a pseudoaneurysm of the internal maxillary artery: a complication of CT-guided biopsy of the masticator space.

A patient presented with transoral hemorrhage 3 months after CT-guided percutaneous biopsy of the masticator space, prompting concern about sentinel hemorrhage from impending carotid artery rupture related to prior radical head and neck surgery and radiation therapy. Angiographic evaluation showed the internal carotid artery to be normal but demonstrated a pseudoaneurysm of the buccal branch of the internal maxillary artery exactly corresponding to the site of prior fine-needle biopsy.

Aneurysm, False↗