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Biomedical subjects

C Toth

Publications and source records attributed to C Toth.

35 records · Page 2Linked to original sources
PubMed1998

Stereotactic cyst wall disruption and aspiration of colloid cysts of the third ventricle.

BACKGROUND: Current strategies of surgical therapy for colloid cysts have been associated with low rates of initial success and high rates of morbidity, mortality and recurrence of cysts. Cyst recurrence following simple stereotactic aspiration has been hypothesized to be due to regrowth of the epithelium composing the cyst wall. METHODS: We propose a procedure involving stereotactic disruption of the colloid cyst wall with the removal of a portion of the cyst wall followed by aspiration of cyst contents as a surgical therapy for colloid cysts. RESULTS: This procedure was performed in 2 female and 3 male patients who were followed for an average of 49 months with all patients demonstrating immediate improvement of symptoms and resolution of the cyst verified with repeat computerized tomography (CT) scans. There was one incidence of recurrence in an asymptomatic patient at 75 months postoperatively. CONCLUSION: We propose that stereotactic partial cyst wall disruption and content aspiration may limit recurrence of colloid cysts, thus offering an advantage over simple stereotactic aspiration alone.

Adult↗
PubMed1998

Maxillary sinus augmentation in the non-human primate: a comparative radiographic and histologic study between recombinant human osteogenic protein-1 and natural bone mineral.

The posterior maxilla has traditionally been one of the most difficult areas to successfully place dental implants due to poor bone quality and close approximation to the maxillary sinus. Sinus augmentation procedures have become a viable means of assuring adequate bone for the placement of dental implants in this area. However, with the techniques currently employed, a considerable variation in the quality of bone attained with the sinus augmentation procedure exists. The purpose of this in vivo study was to evaluate the healing response and bone formation stimulated by 3 doses of recombinant human osteogenic protein-1 (rhOP-1), 0.25, 0.6, and 2.5 mg OP-1 per gram of collagen matrix; natural bone mineral; or collagen matrix alone (control) placed in the maxillary sinus of adult chimpanzees. Results were assessed using clinical, histologic, and radiographic techniques. Radiographic analysis of the computed tomography scans taken at 1 week, and 2.5, 4.5, and 6.5 months revealed a more rapid mineralization with the 2.5 mg OP-1/g collagen matrix and natural bone mineral treatment groups. The incremental bone mineral density (BMD) increase for these 2 treatments from 1 week to 2.5 months was over 2.5 times the increase found with the collagen matrix alone; these 2 treatments also had a higher BMD at the most superior slices evaluated when compared to the other 3 groups. Biopsy specimens were taken at 3.5, 5.5, and 7.5 months and for all 5 treatment groups bone formation was observed at all time points in the majority of the specimens. At 7.5 months the 2.5 and 0.6 mg OP-1/g collagen matrix treatment groups had an increase in the percent bone area when compared to the matrix alone control. In conclusion, these results demonstrate that sinus augmentation with natural bone mineral or 2.5 mg OP-1/g collagen matrix induce comparable radiographic and histologic evidence of bone formation and that both of these treatments performed superior to the control group of collagen matrix alone based upon all methods of evaluation.

Analysis of Variance↗
PubMed1997

Spinal cord stimulation is effective in the management of reflex sympathetic dystrophy.

OBJECTIVE: The purpose of this study was to determine the efficacy of spinal cord stimulation (SCS) in patients with symptoms of reflex sympathetic dystrophy (RSD), a disabling clinical condition with significant consequences of morbidity and loss of productivity. METHODS: We have used epidural SCS for pain control during the past 15 years. An analysis of our records revealed 12 consecutive patients diagnosed as having RSD before undergoing SCS. Eight of the 12 patients had undergone previous ablative sympathectomy. The mean age of the nine men and three women was 38.2 years. All suffered extremity injuries from a variety of causes. RESULTS: All 12 patients experienced relief of pain after trial stimulation and had their systems permanently implanted. At an average of 41 months follow-up, all patients were using their stimulators regularly and only two were receiving adjunctive minor pain medication. The level of pain present pre- and postoperatively was determined by administering a modified McGill Pain Questionnaire and a visual analog scale to each patient. Eight patients reported excellent pain relief, and four patients described good results. Five minor complications occurred. CONCLUSION: SCS is an effective treatment for the pain of RSD, including recurrent pain after ablative sympathectomy. The low morbidity of this procedure and its efficacy in patients with refractory pain related to RSD suggest that SCS is superior to ablative sympathectomy in the management of RSD.

Adult↗
PubMed1997

Deep brain stimulation for intractable pain: a 15-year experience.

OBJECTIVE: During the past 15 years, we prospectively followed 68 patients with chronic pain syndromes who underwent deep brain stimulation (DBS). The objective of our study was to analyze the long-term outcomes to clarify patient selection criteria for DBS. METHODS: Patients were referred from a multidisciplinary pain clinic after conservative treatment failed. Electrodes for DBS were implanted within the periventricular gray matter, specific sensory thalamic nuclei, or the internal capsule. Each patient was followed on a 6-monthly follow-up basis and evaluated with a modified visual analog scale. RESULTS: Follow-up periods ranged from 6 months to 15 years, with an average follow-up period of 78 months. The mean age of the 54 men and 14 women in the study was 51.3 years. Indications for DBS included 43 patients with failed back syndrome, 6 with peripheral neuropathy or radiculopathy, 5 with thalamic pain, 4 with trigeminal neuropathy, 3 with traumatic spinal cord lesions, 2 with causalgic pain, 1 with phantom limb pain, and 1 with carcinoma pain. After initial screening, 53 of 68 patients (77%) elected internalization of their devices; 42 of the 53 (79%) continue to receive adequate relief of pain. Therefore, effective pain control was achieved in 42 of 68 of our initially referred patients (62%). Patients with failed back syndrome, trigeminal neuropathy, and peripheral neuropathy fared well with DBS, whereas those with thalamic pain, spinal cord injury, and postherpetic neuralgia did poorly. CONCLUSION: DBS in selected patients provides long-term effective pain control with few side effects or complications.

Adult↗
PubMed1997

Improvement of limb circulation in peripheral vascular disease using epidural spinal cord stimulation: a prospective study.

Spinal cord stimulation was used in 46 patients for pain associated with lower extremity ischemic vascular disease that was considered to be nonreconstructable. Thirty-nine patients who had a follow-up examination between 2 and 36 months after the procedure form the basis of this report. Thirty (77%) of 39 cases were considered successful. Clinical endpoints indicating failure included amputation, vascular reconstruction, poor pain relief, or hardware malfunction. The transcutaneous partial pressure of oxygen (TcPO2) increased in both target and control feet. In patients with good outcome with a preimplantation TcPO2 of less than 30 mm Hg, TcPO2 increased significantly (p < 0.05). Pulse volume recording improved significantly (p < 0.05) at the thigh, metatarsal, and great toe levels in successfully treated patients. Peak blood flow velocity also showed a significant increase in patients with good outcome (p < 0.05). Patients with a TcPO2 of less than 10 mm Hg following stimulation tended to undergo amputation within the first 3 months. Improvement in pain control, combined with an increase in TcPO2 values that was greater than 10 mm Hg, were significant early predictors of long-term success. An initial increase in peak blood flow velocities (measured in Doppler studies) of greater than 10 mm also signified a good long-term outcome. Spinal cord stimulation appears to be a useful therapeutic modality for controlling pain and improving perfusion in a select group of patients with end-stage ischemic vascular disease considered nonreconstructable. The best results were seen in patients with severe claudication and rest pain without trophic changes in the foot. The mechanism of this beneficial effect is not yet completely understood.

Aged↗
PubMed1996

Identification and mapping of a chromosomal gene cluster of Borrelia burgdorferi containing genes expressed in vivo.

A clone containing a 6.4 kb Borrelia burgdorferi chromosomal DNA insert reacted only with sera from patients with Lyme disease and not with any normal human or rabbit sera. Restriction enzyme analysis indicated that this DNA fragment was located on the B. burgdorferi chromosomal map between rpoB and p22A; its direction of transcription was towards p22A. Sequence analysis suggests that LA006 encodes six proteins: three previously described immunodominant lipoproteins of the 39 kDa Bmp protein family, BmpA, BmpB and BmpC; a 51 kDa MgtE magnesium transporter protein; a 16 kDa protein kinase C inhibitor; and a 56 kDa protein with similarity to an uncharacterized Escherichia coli chromosomal open reading frame.

Amino Acid Sequence↗
PubMed1996

Synergistic activation of transcription by the mutant and wild-type minimal transcriptional activation domain of VP16.

VP16 activates transcription by stimulating initiation, and for this function the aromatic residue at position 442 within its activation domain is critical. Recent studies have suggested that VP16 also stimulates transcriptional elongation. It has been shown that VP16 can activate transcription tethered downstream of the transcription start site to RNA. Here, we analyze the synergistic activation features of hybrid VP16 fusion proteins when tethered simultaneously to RNA downstream of the start site and to DNA upstream of a promoter in order to investigate its role in postinitiation control of transcription. Upon targeting the VP16 activation domain simultaneously to both DNA and RNA, high levels of transcriptional synergism is observed. Importantly, a transcription-defective VP16 minimal activation domain (amino acids 413-453) mutated at critical residue 442 (phenylalanine --> proline) maintained synergism, when bound to RNA, with the DNA-bound wild-type VP16 minimal activation domain. Targeting of this "functionally defective" VP16 minimal activation domain via RNA and an intact activation domain via DNA allowed us to uncover a postinitiation activity for VP16 not previously detected in DNA targeting studies. We suggest that, in addition to stimulating initiation, VP16 also acts at a postinitiation step involving residues other than the critical residue at position 442 within the same 41-amino acid minimal activation domain (amino acids 413-453) required for initiation.

Amino Acid Sequence↗
PubMed1996

Spinal cord stimulation for chronic pain in peripheral neuropathy.

BACKGROUND: Spinal cord stimulation (SCS) has been used for the relief of chronic, intractable pain for over 2 decades. Recent technologic improvements in hardware have resulted in improved clinical outcome. We report our experience with epidural spinal cord stimulation for pain control of peripheral neuropathy for the past 15 years. METHODS: An analysis of our series of 276 patients revealed 30 patients diagnosed with peripheral neuropathy. The mean age of the 16 men and 14 women in the study was 62.4 years. The anatomic sources of pain included thorax, as well as upper and lower limbs. Causes of intractable pain included postherpetic neuralgia, intercostal neuralgia, causalgic pain, diabetic neuropathy, and idiopathic neuropathy. RESULTS: Nineteen patients reported relief of pain on trial stimulation and had their systems permanently implanted. At an average of 87 months' follow-up, 14 of these patients achieved long-term success in control of chronic pain (47% of all patients included in this study). Six patients reported excellent pain relief (> 75% pain relief), eight described good results (> 50% pain relief), and six had poor pain relief (< 50% pain relief). CONCLUSION: SCS is an effective therapy for pain syndromes associated with peripheral neuropathy. Causalgic and diabetic neuropathic pain seem to respond relatively well. whereas postherpetic pain and intercostal neuralgia syndromes seem to respond less favorably to the long-term beneficial effects of SCS. This information will be useful in the selection of patients with peripheral neuropathic pain who could be helped by SCS.

Adult↗
PubMed1996

A normal bias toward a pictorially defined top in line bisection.

BACKGROUND: We set out to determine whether separable visual and representational components underlie normal subjects' upward and distal biases in bisecting vertical and radial lines under visual guidance. METHODS: Thirty-four normal subjects were asked to bisect lines oriented horizontally, vertically, and radially. Human silhouette figures were placed at either end of each line. These figures were presented upright or upside down in order to pictorially define a "top" to each line independent of the actual top of the visual field. RESULTS: Although subjects erred toward the top of the visual field, they also demonstrated a significant bias toward the heads of the figures for lines in all spatial orientations. CONCLUSIONS: This result supports the existence of two biases: one toward the upper visual field, and another toward an internally represented "top" as suggested pictorially. These findings provide further support for the hypothesis that normal subjects' upward and distal biases on bisection of vertical and radial lines under visual guidance have both representational and visual-based components.

Adult↗
PubMed1995

Soluble complement receptor 1 inhibits both complement and granulocyte activation during ex vivo hemodialysis.

Hemodialysis with cellulosic membranes results in both complement and granulocyte activation. We investigated the effects of soluble complement receptor 1 (sCR1), a potent complement inhibitor, on both complement and granulocyte activation in an ex vivo model of dialysis. Measurements were made of complement activation (radioimmunoassay for C3a desArg) as well as granulocyte activation (flow cytometric measurements of reactive oxygen species production, granulocyte CD11b/CD18 (MAC-1) expression and CD62L (L-selectin) expression). sCR1 completely abolished the generation of plasma C3a desArg during ex vivo hemodialysis. Without sCR1, C3a desArg levels rose from 968 +/- 373 ng/ml to 4961 +/- 40 ng/ml by the end of the ex vivo procedure (p < 0.001). sCR1 also completely inhibited MAC-1 upregulation and L-selectin shedding from granulocytes during ex vivo hemodialysis. With sCR1 there was still a statistically significant increase in granulocyte reactive oxygen species production (from 2.42 +/- 0.1 fluorescence channels to 6.47 +/- 0.7 fluorescence channels, p < 0.01) but a 50% inhibition when compared with experiments without sCR1 (3.15 +/- 0.5 to 11.2 +/- 1.9, p < 0.01). We conclude that sCR1 completely abolishes complement activation and changes in granulocyte cell adhesion molecules during ex vivo hemodialysis with cellulosic membranes. sCR1 partially inhibits granulocyte reactive oxygen species formation.

Anaphylatoxins↗
PubMed1995

[Munchmeyer's disease in children].

The clinical features of two children with myositis ossificans progressiva are described. Skeletal malformations can be observed in many sites: hand, femur, tibia and spine. Phalangeal abnormalities (shortened hallux, hallux valgus) are essential to the diagnosis. We recommend systematic roentgenographic examination to search for other skeletal malformations for congenital hallux valgus in young children because it can be the first sign of myositis ossificans progressiva. Progression of disability does not seem to be influenced by any form of medical treatment. Surgical removal of ectopic bone is thought to be followed inevitably by rapid recalcification at the original site.

Abnormalities, Multiple↗
PubMed1990

Carcinoembryonic antigen as a selective enhancer of colorectal cancer metastasis.

Although the serum level of carcinoembryonic antigen (CEA) is directly associated with a poor prognosis in human colorectal carcinoma (CRC), its function is obscure. As a member of the immunoglobulin supergene family, CEA may be involved with intercellular recognition and binding and facilitate attachment of CRC to sites of metastasis. In an experimental metastasis model of CRC in athymic nude mice, a systemic injection of CEA enhanced experimental liver metastasis and implantation in liver by a weakly metastatic CRC. This CRC also selectively bound to CEA that was attached to plastic. Thus, CEA may function as an attachment factor for CRC.

Animals↗
PubMed1986

The effect of temperature, mean arterial pressure, and cardiopulmonary bypass flows on somatosensory evoked potential latency in man.

Median nerve somatosensory evoked potentials were recorded in 21 patients undergoing cardiac surgical procedures utilizing cardiopulmonary bypass, in order to establish the effects of hypothermia, reductions in mean arterial pressure, and alterations in cardiopulmonary bypass flows on evoked potential latency. Induction and maintenance of anesthesia with fentanyl caused a significant prolongation of latency of the first cortical peak. Temperature changes were linearly correlated with changes in latency for peaks recorded from Erb's point (r = -0.843, p less than 0.01) and the contralateral cortex (r = 0.843, p less than 0.01). There was no significant effect of mean arterial pressure or cardiopulmonary bypass flow reductions on latencies under the conditions of this study. Our results emphasize the importance of monitoring peripheral and first cortical peak latencies in evaluating somatosensory evoked potentials. It is suggested that peak latency prolongations beyond those predicted by temperature alterations may be indicative of hypoperfusion.

Adult↗
PubMedDate not supplied

Headache secondary to deep brain implantation.

This article examines the headaches that can develop with deep brain stimulation. We identified 15 (23.4%) of 64 patients who developed chronic headaches following implantation of deep brain stimulation electrodes for relief of chronic pain syndromes. Electrodes were implanted in the periaqueductal gray, sensory thalamus, and internal capsule. None of these 15 patients reported similar headaches prior to the implantation. Although 5 patients were intermittent headache sufferers prior to implantation, they reported post-implantation headaches to be completely different in nature. Our experience suggests that headache syndromes may arise due to disturbance of serotonergic neurotransmission within deep brain structures.

Adult↗
PubMedDate not supplied

Asymptomatic bacteriospermia in infertile men.

The aerobic and anaerobic flora of the semen was examined in 109 men visiting our infertility clinic. Not one specimen was sterile and 107 specimens contained two or more different bacterial species. Anaerobic organisms were found in 63.3% of specimens. We were able to isolate various organisms that have been shown to be spermicidal in vitro (viridans and hemolytic streptococci, Proteus vulgaris and Escherichia coli) from a large number of samples. If the presence of microorganisms in the semen is associated with infertility, it is likely that only certain organisms are involved or that the numbers of organisms must be high for an effect to be seen. The presence of organisms in the semen may also be related to gynecologic infections.

Adult↗