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Biomedical subjects

D A Ross

Publications and source records attributed to D A Ross.

At least 145 records · Page 8Linked to original sources
PubMed1994

A Fleur de Lys modification of the TRAM flap for breast reconstruction.

A major problem of the standard TRAM flap is uncertain vascularity. Many modifications have been made to overcome this problem, but they usually lead to an increase in both the duration and complexity of the operative procedure. The modification described here uses a single muscle pedicle flap, but adds a vertical component comprising the well vascularised tissue above the umbilicus in continuity with the usual horizontal skin flap. This has the advantage of greater volume of available tissue, much improved blood supply, shorter operative time, greater exposure for dissection, a technically more simple procedure, and quicker recovery. The vertical and horizontal skin flaps are approximated as a cone to provide excellent breast projection. All this can be achieved at the cost of a vertical abdominal scar, which is well accepted when explained to patients.

Adult↗
PubMed1994

Institutional maternal mortality in Mali.

OBJECTIVES: To measure the institutional maternal mortality ratio (MMR) in Mali and suggest ways to reduce it. METHODS: Routinely recorded data from 24 health institutions in three regions were reviewed for 1988 to 1992. RESULTS: The overall MMR in the institutions was 201 maternal deaths per 100,000 live births. Hemorrhage, toxemia and infections accounted for 80% of the 360 recorded maternal deaths, almost all of which were preventable. The main reasons why these conditions result in death lie in poor quality and maldistribution of health services, lack of transport and late use of allopathic services. CONCLUSIONS: Maternal mortality is still a major public health problem in Mali, even among the small proportion of women who reach health facilities. Substantial new initiatives are urgently needed to reduce this major cause of preventable adult female mortality.

Adolescent↗
PubMed1994

Uncomplicated stereotactic and open neurosurgical procedures in patients with factor VII deficiency.

Factor VII deficiency is characterized by epistaxis, bruising, hemarthrosis, menorrhagia, gastrointestinal bleeding, hematuria, and intracranial hemorrhage during infancy. Causes of acquired factor VII deficiency include liver disease, Vitamin K deficiency, and warfarin administration. Congenital factor VII deficiency is an autosomal recessive disorder, with the homozygotes having a severe deficiency and the heterozygotes a moderate deficiency of factor VII. Orthopedic, gynecological, cardiothoracic, and abdominal surgical procedures have been successfully performed in patients with factor VII deficiency both with and without factor VII replacement. We present two patients with moderate and moderately severe factor VII deficiency who successfully underwent intracranial procedures using plasma during the perioperative period for factor VII replacement. One patient successfully underwent stereotactic placement of mesial temporal lobe depth electrodes and subdural strip electrodes followed by anterior temporal lobectomy for medically refractory seizures. The second patient successfully underwent craniotomy for an olfactory groove meningioma. No bleeding complications were encountered with any of the three intracranial procedures performed. These cases represent the first reported cases of successful intracranial procedures in patients with factor VII deficiency, other than shunting procedures performed for intraventricular hemorrhage during infancy.

Adult↗
PubMed1994

The central slip tenodesis test for early diagnosis of potential boutonnière deformities.

Disruption of the central slip is the primary defect leading to boutonnière deformity. In the closed injury early diagnosis of this lesion is rarely achieved due to the limitations of current methods and difficulties encountered in assessing a painful finger. We describe a simple, non-invasive method of diagnosis which can be carried out on all patients and with minimal discomfort. This test is also beneficial in monitoring the progress of conservative management of central slip disruption.

Hand Deformities, Acquired↗
PubMed1994

A frame shift mutation in the PMP22 gene in hereditary neuropathy with liability to pressure palsies.

Hereditary neuropathy with liability to pressure palsies (HNPP) has been a associated with a deletion of 1.5 megabases of chromosome 17p. One of four biopsy proven HNPP families that we have studied did not possess this deletion. As the deleted DNA region includes the coding region for a peripheral myelin gene (PMP22), we used single strand conformation analysis to examine this gene for mutations in the non-deleted HNPP family. An abnormal fragment in exon 1 was identified, and sequencing revealed a two base pair deletion in all affected family members. The deletion results in a frame shift, providing strong evidence that this gene has an important role in the pathogenesis of the disease.

Base Sequence↗
PubMed1994

Measurement of the frequency and severity of childhood acute respiratory infections through household surveys in northern Ghana.

BACKGROUND: Methodological issues in the design and interpretation of cross-sectional interview surveys of the prevalence of acute respiratory infections (ARI) were assessed among young children. METHODS: A cross-sectional survey was conducted in approximately 20,000 children in the north of Ghana. Approximately half were administered a questionnaire in which the initial questions about recent illnesses were direct questions about the presence or absence of three specific ARI-related symptoms (cough, rapid breathing, difficulty breathing), while the other half were administered a questionnaire which started with an open-ended question on whether the child was ill, designed to elicit spontaneous responses. A 2-week recall period was used in addition to point prevalence questions for half of the children in each group, while 4 weeks was used for the other half. The results were compared with those from a longitudinal morbidity surveillance system in an adjacent population of children. The repeatability of the responses to each of the symptoms/conditions was assessed in a subsample of the children. RESULTS AND CONCLUSIONS: The point and period prevalence rates of ARI symptoms or conditions based on spontaneously elicited responses were more likely to be valid than those based on prompted responses. Furthermore, using a 2-week recall period appeared to give more valid period prevalence rates than a 4-week recall period. The repeatability of the various ARI questions was not high (kappas 0.14 to 0.49), irrespective of the questionnaire design. Whether these findings will also be true in other populations needs to be assessed.

Acute Disease↗
PubMed1994

Bacterial superantigens in autoimmune arthritis.

Discoveries of the biological properties of bacterial superantigens have given rise to much speculation about their possible role in the pathogenesis of autoimmune diseases. There is an increasing body of data to support these speculations. This field of research has the potential to provide a long-elusive understanding of the mechanisms which underlie microbial involvement in the pathogenesis of autoimmune polyarthritides.

Animals↗
PubMed1994

Toward functional magnetic stimulation (FMS) theory and experiment.

This paper examines the use of magnetic fields to functionally stimulate peripheral nerves. All electric fields are induced via a changing magnetic field whose flux is entirely confined within a closed magnetic circuit. Induced electric fields are simulated using a nonlinear boundary element solver. The induced fields are solved using duality theory. The accuracy of these predictions is verified by saline bath experiments. Next, the theory is applied to the stimulation of nerves using small, partially occluded ferrite and laminated vanadium permendur cores. Experiments demonstrate the successful stimulation of peripheral nerves in the African bullfrog with 11 mA, 153 mV excitations. These results offer a new vista of possibilities in the area of functional nerve stimulation. Unlike functional electric stimulation (FES), FMS does not involve any half cell reactions, and thus would not have the commensurate FES restrictions regarding balanced biphasic stimulation, strength duration balances, and oxidation issues, always exercising care that the electrodes remain in the reversible operating regime.

Action Potentials↗
PubMed1994

Group A streptococcal antigens and superantigens in the pathogenesis of autoimmune arthritis.

Evidence from repeated clinical observations and from a variety of experimental approaches implicates group A streptococci in the pathogenesis of the autoimmune arthritides. Several streptococcal antigens and superantigens have now been characterized and their properties suggest that they may be involved in the mechanisms which underlie these diseases, although other antigens and superantigens yet to be discovered may also be involved. The association between group A streptococcal infection and autoimmune arthritis offers a useful model for providing a long-elusive understanding of the role of bacterial infection in the pathogenesis of autoimmune disease.

Animals↗
PubMed1994

Evidence of allelic imbalance of chromosome 6 in human astrocytomas.

Transfer of human chromosome 6 can suppress the malignant phenotype of melanoma. Because of the neural ectoderm origin of melanoma and since up to 30% of gliomas have abnormalities involving chromosome 6, we performed restriction fragment length polymorphism analysis to determine the importance of allelic loss on chromosome 6 in gliomas. DNA samples from tumor and white blood cells were obtained from patients with pathologically verified gliomas. Of the 20 paired samples, there were two gangliogliomas and one grade I, four grade II, two tumors labeled "low grade," two grade III, and nine grade IV astrocytomas. DNA was hybridized with polymorphic probes D6S29 (6p21), c-myb (6q23.3-24), SOD2 (6q25), D6S37 (6q26), and ESR (6q27). All grades of tumor revealed areas of genetic loss. Allelic imbalance (AI) was present in 11 of 47 (23%) of informative loci on 6q and four of seven (57%) on 6p. Loci at 6p21 and 6q26 were most often lost. In contrast, probes from three non-chromosome 6 loci demonstrated a combined total of 11% allelic loss. Genetic loss from chromosome 6 is a frequent event in glial neoplasms.

Alleles↗
PubMed1994

Papillary squamous neoplasms of the head and neck.

Papillary squamous neoplasms of the upper respiratory tract are rare variants of squamous cell carcinoma and are related temporally to proliferative verrucous leukoplakia. Fifty-two cases of papillary squamous neoplasms were selected from 2366 cases of squamous cell carcinoma. This is the first study to characterize the biological behavior of papillary squamous neoplasms. Papillary squamous neoplasms exhibit two distinct, yet sometimes overlapping, histologic patterns including an exophytic papillary and an inverting verrucous morphologic appearance. A high rate of synchronous or metachronous lesions were found, especially with the inverting-type of papillary squamous neoplasm. Stage T3 and T4 lesions had a high rate of neck metastasis. Early surgical intervention and close long-term follow-up is mandatory.

Adult↗
PubMed1994

Lack of association between vitamin A status and measures of conjunctival epithelial integrity in young children in northern Ghana.

OBJECTIVE: To investigate the association between vitamin A status and conjunctival epithelial function in young children in rural northern Ghana and to consider whether impaired epithelial function was associated with increased measures of systemic infection in these children. DESIGN: Children were selected from the Ghana Vitamin A Supplementation Trials' Child Health Study, a randomized, double-blind, placebo-controlled trial of the effect of vitamin A supplementation on morbidity. Treatment group and serum retinol concentrations were used as measures of vitamin A status, conjunctival impression cytology and tear IgA concentrations as measures of conjunctival epithelial integrity, and serum immunoglobulin and alpha 1-acid glycoprotein concentrations as indicators of chronic or acute systemic infection. SUBJECTS: Children 13-64 months old. INTERVENTION: 60 mg retinol as retinyl palmitate every 4 months for 1 year. RESULTS: Vitamin A status was not significantly associated with epithelial integrity nor with measures of systemic infection. Impaired conjunctival epithelial integrity was also not associated with increased systemic infection. CONCLUSIONS: There was no evidence for a major role of improved epithelial integrity and function on the biochemical indices of chronic or acute systemic infection after vitamin A supplementation. These data support the observations in the main study that vitamin A supplementation did not improve conjunctival impression cytology nor decrease the prevalence of most morbidity symptoms.

Child Nutritional Physiological Phenomena↗
PubMed1994

[15O]H2O positron emission tomography determination of cerebral blood flow during balloon test occlusion of the internal carotid artery.

PURPOSE: To determine the utility of [15O]H2O positron emission tomography (PET) for the quantitative determination of cerebral blood flow in patients undergoing balloon test occlusion of the internal carotid artery. METHODS: Twenty-two [15O]H2O PET cerebral blood flow studies were completed on 20 patients for whom temporary or permanent occlusion of the internal carotid artery was being considered because of skull base tumor or internal carotid artery aneurysm. In each study, cerebral blood flow was determined during temporary balloon internal carotid artery occlusion, and again after deflation and removal of the balloon from the internal carotid artery. RESULTS: Patients were divided into three groups based on clinical and cerebral blood flow response to balloon test occlusion. Studies were classified as group I when associated with no clinical symptomatology and with a cerebral blood flow decrease of less than 10 mL/100 g per minute (16 of 22 patients); as group II when there was no clinical symptomatology and cerebral blood flow fell to 25 to 35 mL/100 g per minute on the occluded side (5 of 22); and as group III when the patient was clinically unable to tolerate test occlusion and had a cerebral blood flow of less than 20 mL/100 g per minute on the occluded side (1 of 22). Neurologic sequelae developed in none of the eight group I patients later undergoing permanent internal carotid artery occlusion. Cerebral infarction developed subsequently in the one group II patient who underwent internal carotid artery occlusion. CONCLUSION: During internal carotid artery balloon test occlusion, [15O] H2O PET determination of cerebral blood flow allows rapid quantitative determination of cerebral blood flow throughout the entire brain, predicting the adequacy of collateral flow after permanent occlusion. All patients were able to tolerate the [15O]H2O PET cerebral blood flow determination, and there were no complications of the procedure.

Aneurysm↗
PubMed1994

A special cyst puncture catheter for use in thick-walled or mobile intracranial cysts.

Having encountered a number of thick-walled or mobile symptomatic intracranial cysts that have resisted stereotactic puncture with standard blunt-ended ventricular catheters, the authors have designed a cyst puncture catheter that has a number of features helpful in overcoming this problem. The catheter and its use are described, and examples of difficult-to-puncture cysts are given.

Brain Diseases↗
PubMed1994

Giant Rathke cleft cyst.

The preoperative diagnosis for an unusual skull base lesion was chordoma. The combination of imaging, pathologic, and surgical findings suggests the diagnosis of Rathke cyst.

Chordoma↗
PubMed1993

Myxopapillary ependymoma. Results of nucleolar organizing region staining.

BACKGROUND: Although myxopapillary ependymomas are generally benign with a tendency for slow growth and local recurrence, they are capable of spread within the nervous system and of extraneural metastasis. Histologic features have not been helpful in determining which patients are at risk for recurrence or dissemination, making management decisions difficult. METHODS: A retrospective review was conducted of 14 cases of myxopapillary ependymoma. The nucleolar organizing region (NOR) staining method was used to determine if this technique was useful in the management of these tumors. RESULTS: Five patients had total resections of encapsulated lesions, four had total resections of adherent tumors, and four had subtotal resections. Twelve received postoperative radiation therapy. With a mean follow-up of 80 months, 12 patients are well and disease-free. Two patients have had recurrences after surgery and irradiation, leading to death in one and disability in the other. The mean number of NOR per cell in eight specimens ranged from 0.4-1.64. The patient who died with intracranial spread had the highest number of NOR per cell. CONCLUSIONS: Based on these data and a review of the literature, it is recommended that radiation be delayed until recurrence in tumors that have been totally resected. Local radiation therapy may be indicated in subtotally resected tumors. NOR staining shows promise in predicting the likelihood of spread of tumor. Patients with myxopapillary ependymomas should be followed indefinitely because of the potential for late recurrence, even after aggressive therapy.

Adolescent↗