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Biomedical subjects

J Tew

Publications and source records attributed to J Tew.

At least 19 recordsLinked to original sources
PubMed2001

Follicular dendritic cell accessory activity crosses MHC and species barriers.

Productive follicular dendritic cell (FDC)-B cell interactions appear to involve critical ligand-receptor interactions. Immune complexes (IC) on FDC activate complement and provide FDC with a complement-derived CD21 ligand (CD21L), which bind CD21, while antigen in the IC binds on the B cell-BCR. Further, FDC-FcgammaRIIB binds Fc regions of antibodies in IC and reduces coligation of BCR and FcgammaRIIB minimizing an inhibitor of B cell activation. Given that Fc receptors and complement receptors bind immunoglobulins and complement fragments of other species, we reasoned that FDC accessory activity should cross MHC and species barriers. This prediction was tested using memory lymphocytes from OVA-immune mice and TT-immune humans in combination with FDC from murine lymph nodes and human tonsils. Human and murine FDC converted IC into potent immunogens (specific antibody increased from background to thousands of ng / ml). MHC barriers did not restrict this activity and human FDC worked with murine lymphocytes and murine FDC worked with human lymphocytes. Furthermore, stimulation via MHC-dependent allogeneic or zenogeneic mechanisms did not promote antibody production by FDC. Polyclonal responses stimulated by lipopolysaccharide and pokeweed mitogen were also promoted (10 - 100-fold) and anti-CD21 blocked FDC activity. These results substantiate the hypothesis that FDC are necessary for strong recall responses and that FDC-CD21L is critical.

Animals↗
PubMed1999

Clonal origin of recurrent meningiomas.

Meningiomas are common intracranial and intraspinal tumors. They are treated primarily by surgical resection. Meningioma recurrence following surgery is frequent despite advances in microneurosurgery. However, it is not clear whether recurrent meningiomas, close or distant to the primary resection site, arise from incomplete resection, dissemination of tumor fragments or from independent tumor growth. In order to address the question of clonality in recurring meningiomas, we examined a series of five patients with a total of 14 tumors for X-chromosome inactivation in the tumor tissues. Four patients with a total of 11 meningiomas were informative for polymorphisms either in the PGK or the AR genes. All recurrent meningiomas were found to be clonal with respect to the primary lesions. This finding suggests a common molecular pathogenesis of primary meningioma and subsequent recurrences (p<0.01). In a sixth patient, we analyzed the NF2 gene for mutations in the primary and 5 recurrent meningiomas. All six lesions carried the identical NF2 mutation, strongly indicating a common origin for these tumors. We conclude that recurrent meningiomas usually arise from dissemination of tumor fragments, most likely at the time of the first surgical resection. Our data should alert to the potential of meningioma cells for seeding during surgical procedures.

DNA Mutational Analysis↗
PubMed1999

Early surgical treatment for supratentorial intracerebral hemorrhage: a randomized feasibility study.

BACKGROUND AND PURPOSE: The safety and the effectiveness of the surgical treatment of spontaneous intracerebral hemorrhage (ICH) remain controversial. To investigate the feasibility of urgent surgical evacuation of ICH, we conducted a small, randomized feasibility study of early surgical treatment versus current nonoperative management in patients with spontaneous supratentorial ICH. METHODS: Patients with spontaneous supratentorial ICH who presented to 1 university and 2 community hospitals were randomized to surgical treatment or best medical treatment. Principal eligibility criteria were ICH volume >10 cm(3) on baseline CT scan with a focal neurological deficit, Glasgow Coma Scale score >4 at the time of enrollment, randomization and therapy within 24 hours of symptom onset, surgery within 3 hours of randomization, and no evidence for ruptured aneurysm or arteriovenous malformation. The primary end point was the 3-month Glasgow Outcome Scale (GOS). A good outcome was defined as a 3-month GOS score >3. RESULTS: Twenty patients were randomized over 24 months, 9 to surgical intervention and 11 to medical treatment. The median time from onset of symptoms to presentation at the treating hospitals was 3 hours and 17 minutes, the time from randomization to surgery was 1 hour and 20 minutes, and the time from onset of symptoms to surgery was 8 hours and 35 minutes. The likelihood of a good outcome (primary outcome measure: GOS score >3) for the surgical treatment group (56%) did not differ significantly from the medical treatment group (36%). There was no significant difference in mortality at 3 months. Analysis of the secondary 3-month outcome measures showed a nonsignificant trend toward a better outcome in the surgical treatment group versus the medical treatment group for the median GOS, Barthel Index, and Rankin Scale and a significant difference in the National Institutes of Health Stroke Scale score (4 versus 14; P=0.04). CONCLUSIONS: Very early surgical treatment for acute ICH is difficult to achieve but feasible at academic medical centers and community hospitals. The trend toward less 3-month morbidity with surgical intervention in patients with spontaneous supratentorial ICH warrants further investigation of very early clot removal in larger randomized clinical trials.

Cerebellar Diseases↗
PubMed1998

The effect of smoking on individuals with minimal periodontal destruction.

Recent studies have demonstrated that smoking is associated with periodontal destruction. The majority of these studies have focused on periodontal disease groups with moderate or severe periodontal destruction. Additionally, there have been few reports investigating the relationship between smoking and gingival recession. The goal of this report was to investigate the effect of smoking on periodontal destruction and recession in subjects with minimal or no interproximal attachment loss. This is a cross-sectional study of 142 non-smoking subjects and 51 smoking subjects. Subjects could have no more than one tooth with a site of interproximal attachment loss > or =2 mm. Subjects could, however, have attachment loss associated with recession. For three different methods of summarizing attachment loss measurements at a subject level, including average attachment loss, percentage of teeth with one site of 2 mm of attachment loss, and the percentage of teeth with one site of 5 mm of attachment loss, smoking subjects had approximately twice as much attachment loss than their non-smoking counterparts. Smoking subjects also had significantly greater recession (P < 0.05) [0.056+/-0.017 mm] than non-smoking subjects (0.025+/-0.005 mm). Recession sites occurred primarily on the facial surface of maxillary molars and bicuspids and mandibular central incisors and bicuspids. The results suggest a strong association between smoking and both attachment loss and recession in subjects who have minimal or no periodontal disease.

Adolescent↗
PubMed1997

Stereotactic radiosurgery for the treatment of brain metastases. Results of a single institution series.

BACKGROUND: Stereotactic radiosurgery is being used with increasing frequency for the treatment of brain metastases. Optimal patient selection and treatment factors continue to be defined. This study provides outcome data from a single institutional experience with radiosurgery and identifies parameters that may be useful for the proper selection and treatment of patients. METHODS: Eighty-four patients underwent stereotactic radiosurgery for brain metastases between September 1989 and November 1995. Seventy-nine patients (93%) were treated at recurrence after previous whole brain radiotherapy. Patients had between 1 and 6 lesions treated with a median minimum tumor dose of 1600 centigrays (cGy). Thirty-eight patients (45%) had active extracranial disease at the time of radiosurgery. RESULTS: Median survival for the entire group was 43 weeks from the date of radiosurgery and 71 weeks from the original diagnosis of brain metastases. Patients with 1 or 2 metastases had significantly improved survival compared with patients with > or = 3 metastases (P = 0.02), and patients without active extracranial tumor survived longer than those with extracranial disease (P = 0.03). Median time to failure for 145 evaluable lesions was 35 weeks. Local control was significantly improved for radiosurgery doses of > 1800 cGy, and for melanoma histology. CONCLUSIONS: These results are comparable to reports of patients treated with resection and significantly superior to results observed after whole brain radiotherapy. The authors conclude that stereotactic radiosurgery is an effective, low risk treatment for extending the survival of patients with recurrent brain metastasis. Although survival is best for patients with < or = two lesions and no active extracranial disease, selected patients with > two lesions or active extracranial tumor may benefit as well.

Actuarial Analysis↗
PubMed1997

Spinal dural arteriovenous fistulas: recognizing the spectrum of magnetic resonance imaging findings.

Spinal dural arteriovenous fistulas are the most common type of vascular malformation to involve the spinal cord. In this report, we describe and analyze the various magnetic resonance imaging (MRI) findings of spinal dural arteriovenous fistulas in order to increase awareness and prompt timely diagnosis. We reviewed 14 patients evaluated and treated for spinal dural arteriovenous fistulas over a seven year period, with special attention to findings on MRI. All patients had regions of increased cord signal on T2-weighted MRI, with corresponding hypointense signal on T1-weighted images in 11 patients (79 percent). Thirteen (93 percent) of 14 patients had focal increased cord caliber and eight (57 percent) had prominent intradural vessels. Cord enhancement was observed in all seven patients who were administered contrast and two patients had enhancement of intradural vessels. These imaging findings are relatively nonspecific, but should lead to further investigation with myelography or arteriography in the appropriate clinical setting.

Adult↗
PubMed1997

The effect of race, smoking and immunoglobulin allotypes on IgG subclass concentrations.

In previous studies we have demonstrated that serum IgG subclass concentrations are influenced by both race and periodontal disease diagnosis. Furthermore, we have shown that smoking habits modify the concentrations of some IgG subclasses in specific racial and diagnostic groups. In view of a large amount of data showing strong associations between immunoglobulin allotypes and IgG subclass concentrations we have investigated the effects of race, smoking and IgG allotype on IgG subclass concentration in a population of subjects with or without various forms of periodontitis. The results indicated that there are complex relationships between these factors in their effects on individual IgG subclass levels, and that effects unique to black or white subject groups, or to specific periodontal diagnostic groups and racial subgroups, were evident. In blacks with chronic adult periodontitis IgG1 was lower in smokers, while in generalized early-onset periodontitis patients IgG2 was lower in smokers. IgG4 was independently affected by gender (males higher), smoking (smokers lower) and GM23 (GM23 positive subjects higher), in black subjects only. In white subjects, complex relationships between smoking and allotypic markers were noted but no influence of periodontal diagnosis was found. White GM23 negative subjects who smoked had lower levels of IgG1 than GM23 positive subjects. White GM2 negative subjects who smoked had lower levels of IgG2, than did those who did not smoke. In contrast, smoking had no effect on IgG2 levels in GM2 positive subjects. Thus, in addition to immunoglobulin allotype, smoking is associated with IgG subclass concentrations; furthermore, in black subjects, periodontal diagnosis, gender and smoking all influence IgG subclass concentrations. These results demonstrate that genetic and environmental factors can interact to influence levels of individual subclasses.

Adult↗
PubMed1994

Management of intracerebral hemorrhage in a large metropolitan population.

The management of all patients with spontaneous, nonaneurysmal intracerebral hemorrhages that occurred in the 1.26 million population of Greater Cincinnati during 1988 was reviewed. Of the 188 patients with intracerebral hemorrhage, 26 had operative removal of their intracerebral hemorrhage, and 8 had removal of their intracerebral hemorrhage and an arteriovenous malformation. In 15 of the 34 patients, the operation was performed within 12 hours of onset. The operative removal of parenchymal hemorrhages was performed in 29% of cerebellar, 24% of lobar, 13% of deep, and 10% of pontine hemorrhages. Admission Glasgow Coma Scale scores were similar for operated and nonoperated patients (11 +/- 3 versus 11 +/- 3), but operated patients were significantly younger (58 +/- 17 versus 72 +/- 15 yr), were more likely to have a lobar hemorrhage (64 versus 43%) or a cerebellar hemorrhage (29 versus 7%), and had larger parenchymal hemorrhages (50 +/- 31 versus 37 +/- 38 ml). Operated patients had a borderline lower 30-day mortality (25%) than nonoperated patients (46%), but the overall morbidity and mortality for the two groups did not differ significantly. Patients undergoing an early operation were more critically ill preoperatively and had a greater 30-day mortality (45%) than did those patients undergoing a late operation (12%). Half of the 43% mortality for all hospitalized cases occurred during the first 2 days after onset, and two-thirds occurred during the first 4 days. Only 12% of all patients had a minor handicap or better at 30 days. Neurosurgeons in our community performed operative removal of parenchymal hemorrhage in nearly one fifth of all patients with intracerebral hemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Parent power.

Giving parents responsibility for holding their children's health records has improved the quality of information, Jo Tew and Nadia Deadman discover.

Child Health Services↗
PubMed1992

Selective medicals at school entry.

This paper describes a selective procedure for use at school entry based on information from pre-school surveillance, parental questionnaires and class reviews. The pilot study in use over two years shows that the number of new conditions found at age 5 are relatively few in number and the extra time available can be used more appropriately for those with health problems affecting school progress. The job satisfaction for both nurses and doctors is increased and the parents are more fully involved with their child's health and progress. The introduction of a new computerised Child Health System and Parent Held Record will further enhance this system.

Child, Preschool↗
PubMed1991

Influence of a carbohydrate-electrolyte beverage on performance and blood homeostasis during recovery from football.

This study compared the efficacy of a 7% glucose polymer beverage containing electrolytes (GP) versus a nonnutrient, nonelectrolyte placebo (P) in maintaining blood homeostasis during recovery from football and determined whether consumption of the GP beverage improved anaerobic performance immediately after football competition when compared with the placebo. Forty-four high school football players participated in a 50-play scrimmage designed to simulate game conditions. At each of six periods before and during the scrimmage, players consumed 170 ml of the GP or P beverage. Eight maximal-effort 40-yd sprints (40-sec rest intervals) were performed before and after the scrimmage to assess the decrement in anaerobic performance from the scrimmage. Venous blood samples were drawn before and after the scrimmage and analyzed. The pre- to postscrimmage differences in mean and peak sprint velocities did not differ between treatments, nor did body weight and plasma. In contrast, the percent decrease in plasma volume was significantly greater in the P group. Postscrimmage increases in glucose and insulin were greater in the GP group. These data suggest that CHO-electrolyte drinks do not prevent a decline in anaerobic performance when compared to water, but a CHO-electrolyte drink is more effective in maintaining PV than water during recovery from anaerobic exercise.

Adolescent↗
PubMed1989

Polyclonal B-cell activation in periodontitis.

The evidence that periodontitis-associated bacteria contain potent PBA factors is very strong. Clearly, antibodies directed against non-oral antigens are produced in the inflamed periodontal lesion, and PBA appears to contribute to that production. It is also clear that B cells and plasma cells are the major cell types in the periodontal lesion. Furthermore, alterations in the regulation of B-cell responses to PBA factors are associated with severe periodontal disease. However, evidence demonstrating that activated B cells and plasma cells are directly involved in the pathogenic mechanisms leading to destruction of the periodontal support is still circumstantial. Polyclonal B-cell activation and potential pathways by which PBA-stimulated cells could be involved in periodontal destruction remain largely hypothetical. It appears that IL-1 is an important osteoclast-activating agent, and that LPS, which is a potent PBA factor in many systems, can elicit IL-1 production by B cells as well as by the monocyte/macrophage lineage. Recent data indicating that IL-1 is produced by numerous malignant B-cell lines lend support for the idea that B-cell IL-1 could be important in bone resorption. It is also likely that polyclonal activation may lead to production of autoantibody such as anti-type I and anti-type III collagens, and the destruction of self tissues through ADCC reactions, immune complex formation, and complement activation. Further research is needed to determine how the B cell/plasma cell may participate in tissue injury in periodontitis, and how the B-cell response to PBA factors is regulated.

Animals↗
PubMed1987

An evaluation of transmission spectroscopy (lightscanning) in the diagnosis of symptomatic breast lesions.

A prospective study of transmission spectroscopy (lightscanning) has been performed on 285 women presenting with symptomatic breast disease to one outpatient clinic. Of the 41 patients with histologically confirmed breast cancer lightscanning detected 36 (87.8%). In the study group 164 patients had both lightscans and mammography performed and, of the 30 biopsy-proven carcinomas in this group, lightscanning detected 26 (87%) and mammography 25 (83%). Lightscanning was positive in five of the six non-invasive breast cancers and in 13 of the 15 invasive carcinomas 2 cm or less in diameter. No carcinoma was misdiagnosed as benign when the results of both investigations were combined.

Adolescent↗
PubMed1983

Extracranial carotid artery aneurysms.

Carotid artery aneurysms are rare, however, serious complications may result--namely, rupture, thrombosis, or emboli. Five distinct clinical types of aneurysms are reported with different symptoms and treatment. Fusiform, saccular, false, and mycotic aneurysms are best treated with interposition autogenous vein grafting. Spontaneous dissection aneurysms are best treated initially with anticoagulation and follow-up angiography. Recanalization is the usual result. Meticulous surgical technique to prevent perioperative emboli is essential to prevent central nervous system complications.

Adult↗
PubMed1978

Large suprasellar aneurysms imitating pituitary tumour.

Two patients had large (20--30 mm) suprasellar aneurysms with clinical findings resembling an expanding pituitary tumour. One aneurysm was giant (30 mm). Its delayed diagnosis for six years led to severe chiasmal compression. The other aneurysm was compressing the optic nerve. Visual improvement resulted after surgery.

Carotid Artery, Internal↗