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Biomedical subjects

K Ott

Publications and source records attributed to K Ott.

At least 37 records · Page 2Linked to original sources
PubMed2001

Risk management in a community Gamma Knife unit.

OBJECTIVE: The records of the San Diego Gamma Knife Center were retrospectively reviewed for unprogrammed events as part of a risk management assessment. MATERIALS AND METHODS: Review was made of the physicist notes of the first 1,000 patients successfully treated at the center. This encompassed 1,020 stereotactic frame placement procedures, accompanied by Gamma Knife radiosurgery in 98.0% of intended cases. A total of 7,145 Gamma Knife shots were delivered to 1,509 lesions. RESULTS: Of the 43 unprogrammed events documented, 8 were patient related and 14 were related to lesion growth or location; these were considered unavoidable. Further, one event was related to dose administration, 5 to diagnosis, 15 to technique; these were considered potentially avoidable. This yielded an avoidable error rate of 2.1% per patient, 1.4% per lesion treated, and 0.29% per shot. It was clear that more avoidable errors occurred early in the center's operation, consistent with a learning curve. Review of individual physician's cases revealed none appeared more likely to have an avoidable event. CONCLUSIONS: Consistently high quality may be achieved at a community-based Gamma Knife center if sufficient multidisciplinary involvement is achieved.

Community Health Centers↗
PubMed2001

[Multimodality therapy concepts in esophageal carcinoma].

The role of preoperative chemotherapy for esophageal cancer still remains controversial. Only one study of the recently published, randomized controlled trials in potentially resectable esophageal cancer has shown improvement in survival by preoperative chemotherapy compared to surgery alone. Nevertheless, there has been a consistent observation that in patients who respond to preoperative therapy survival was significantly prolonged. Therefore, a diagnostic test that allows prediction of response is considered to be crucial for the future use of preoperative chemotherapy in patients with esophageal cancer. Molecular markers for response prediction and reliable non-invasive techniques such as FDG-PET are not yet established. At the moment therefore responder should undergo esophagectomy for definitive curative treatment, whereas non-responder may undergo individualized salvage therapy.

Adenocarcinoma↗
PubMed2001

[How can the effectiveness of multimodality therapy concepts be evaluated? From the viewpoint of the pathologist].

Prognostically relevant histopathological grading of tumor regression (grades I-III) is possible, although laborious. Morphological changes after chemotherapy indicate a specific response to treatment with central fibrosis and residual tumor islands in the periphery. Prognostic factors, such as TNM categories, UICC-R status, tumor size, and lymphangiosis, which are not intrinsic part of regression grading still correlate with patient survival.

Combined Modality Therapy↗
PubMed2000

[Does the new UICC classification allow better prognostic assessment for ductal pancreatic carcinoma?].

INTRODUCTION: To compare treatment results an international established classification is necessary. In 1997 the TNM classification of 1992 was modified. METHODS: Between 1983 and 1997, 159 patients with a ductal carcinoma of the pancreas underwent resection. All data of the resected specimens were documented in standardized manner prospectively in a protocol that offered ready transfer of the collected data to a new classification. The TNM categories and stage groupings were transferred to the new UICC classification of 1997 and analyzed in comparison to the classification of 1992. RESULTS: The inclusion of a pT4 category equivalent to the other GI tumors made a new stage grouping necessary. Also division into pN1 a and pN1 b was established. According to the clinical experience only few tumors in early stages (pT1/2 and stage I) were observed in the new classification. There was a significant improval in the patient's distribution to the new stage grouping because of the homogeneous groups. In comparison to the 1992 classification the new stage II shows a relevant prognostic value and a significant difference to stage III. CONCLUSION: We conclude that the new UICC classification relates to prognosis better than the old classification.

Adenocarcinoma↗
PubMed2000

Hepatitis C virus genotypes in Estonia.

Distribution of hepatitis C virus (HCV) geno(sub)types among 215 Estonian patients hospitalized with acute or chronic hepatitis and with HCV RNA-positive sera was investigated. For genotyping, both multiplex PCR with subtype-specific primers of the core region and RFLP analysis of cDNA of the 5' NCR region were used. These two methods permitted a correct characterization of genotypes, a more truthful characterization of mixed infections, and combined use of single-tube performances. They revealed, respectively, 200 and 202 (93.0% and 93.9%) HCV-positive samples of sera, subtype 1a- 0.9% and 0.9%, 1b- 56.3% and 64.2%, 3a- 13.9% and 22.3%, 2a- 6.5% and 5.6%, type 4 0.5% and 0%, mixed infections- 13.5% and 0%, and unidentified- 1.4% and 0.9%. In the majority of cases (84.7%) both methods gave completely or partially concordant results; in mixed infections, as determined by subtype-specific PCR, only one subtype was revealed by the RFLP method. In the remaining 15.3% of the cases (Ohno- 7.0%, RFLP- 8.3%) only one of the methods was positive. The epidemiological analysis of the dynamics of the subtypes' relative participation may indicate increasing 3a and decreasing 1b subtype infection during recent years.

Acute Disease↗
PubMed2000

Malformations in maxillary incisors: case report of radicular palatal groove.

This report describes malformations of anterior teeth and a case of a palatal radicular groove in an upper lateral incisor with periodontal complications. The patient was first diagnosed with an endodontic problem. Endodontic treatment alone failed to resolve the pain. Therefore, after the palatal groove had been properly diagnosed, a palatal flap procedure was carried out including removal of the granulation tissue and careful scaling and root planing of the area with the groove. No odontoplasty was done. Endodontic therapy of the tooth was completed and periapical healing was evident. The treatment effectively reduced the gingival probing depth and led to an asymptomatic tooth.

Adult↗
PubMed2000

Loss of heterozygosity and microsatellite instability as predictive markers for neoadjuvant treatment in gastric carcinoma.

We analyzed a group of gastric carcinomas treated with a cisplatin-based neoadjuvant chemotherapy regimen for microsatellite instability (MSI) and loss of heterozygosity (LOH) to determine whether there is any relation between microsatellite alterations and therapy response. Pretherapeutic endoscopic biopsies of 37 patients were studied at 11 microsatellite loci. Thirteen (35%) had a complete or partial clinical response (responders), and 24 (65%) had only a minor or no response (nonresponders). High-grade MSI was found in two tumors, both nonresponders, whereas low-grade MSI was found in five biopsies, including three non-responders and two responders. Regarding LOH, the most obvious differences between the groups were observed on chromosome 17p13, the location of the p53 gene, with 7 of 12 (58%) and 3 of 20 (15%) of the informative tumors exhibiting LOH in responders and nonresponders, respectively (P = 0.018). A statistically significant difference was also observed in the fractional allelic loss (FAL) ratio of the groups. Among the 13 responding patients, 7 (54%) tumors exhibited high FAL (>0.5-0.75), 2 (15%) showed medium FAL (>0.25-0.5), and 4 (31%) demonstrated low FAL values (0-0.25), whereas among the 22 nonresponding patients, 2 (9%) tumors showed high FAL, 5 (23%) showed medium FAL, and 15 (68%) showed low FAL (P = 0.020). These data suggest that LOH at chromosome 17p13 is associated with a good clinical response to cisplatin-based chemotherapy, suggesting that altered p53 function might render cells more sensitive to therapy. Furthermore, the association of FAL with therapy response indicates that gastric carcinomas with a high level of chromosomal alteration may be more sensitive to this type of chemotherapy.

Adult↗
PubMed1999

Diffuse type gastric and lobular breast carcinoma in a familial gastric cancer patient with an E-cadherin germline mutation.

E-Cadherin alterations have been reported frequently in sporadic diffuse type gastric and lobular breast carcinomas. Germline mutations of this gene have been identified recently in several gastric cancer families. We analyzed seven patients with a family history of the disease who had diffuse type gastric cancer diagnosed before the age of 45 for germline mutations in CDH1, the gene encoding the E-cadherin protein. We identified a frameshift mutation in exon 3 in one patient with a strong family history of gastric cancer. The same germline mutation was found in the patient's mother, who had metachronous development of lobular breast and diffuse type gastric carcinomas. Immunohistochemistry for E-cadherin protein expression revealed an abnormal staining pattern in both of these tumors, suggesting complete inactivation of the cell adhesion molecule. Thus, our finding suggests that besides diffuse type gastric cancer, lobular breast carcinomas may be associated with germline CDH1 mutations.

Adult↗
PubMed1998

Bronchogenic cyst of the esophagus with high tumor marker levels--a case report and review of the literature.

Bronchogenic cysts of the esophagus are rare in comparison with the relatively common bronchogenic cyst of the lung. Only a few cases have been reported in literature since 1930. We report on a case of a 43-old-male with a bronchogenic cyst in the distal esophagus, which was misdiagnosed as a malignant esophageal tumor based on preoperative imaging and high levels of the tumor markers CA 19-9 and CA 125.

Adult↗
PubMed1998

An algorithm for the empirical determination of intracranial stereotactic targets.

The determination of empirical targets for functional brain lesions is usually made with graphical techniques using CT or MR software. Geometrical errors occur in the method when the intercommissural line and plane of the third ventricle are not parallel and orthogonal to transaxial images. A mathematical algorithm can be used to calculate target coordinates from the coordinates of the anterior commissure, the posterior commissure, and the position of a third point within the inferior, third ventricle. These coordinates may be determined in any image plane in stereotactic space. By supplying the distance of the target from the mid-point of the intercommissural line, the distance lateral and inferior to the line, target coordinates are computed. This overcomes geometrical errors of previous graphical methods.

Algorithms↗
PubMed1996

A comparison of craniotomy and Gamma Knife charges in a community-based Gamma Knife Center.

The hospital charges for all craniotomies and transsphenoidal procedures were gathered for a 4-year period from a single, non-profit hospital serving San Diego. Calif., USA. Of the individuals in this community 65% are covered by a variety of managed health care programs which have greatly discounted hospital receipts on a per diem or capitated payment basis. A total of 104 operative cases were identified. Forty-six patients (44%) were judged to have been eligible for Gamma Knife surgery. The average hospital charge for intracranial surgery on Gamma-Knife-eligible individuals was 14% greater than the nominal Gamma Knife surgery charge would have been. The complication rate for treated Gamma-Knife-eligible individuals was 15% including blindness in one eye after removal of a tuberculum sella meningioma, and hemiplegia following a delayed postoperative hemorrhage after arteriovenous malformation resection in another patient. Actual hospital net receipts were 55% of charges and probably approached the true hospital cost per procedure. When these hospital receipts were compared to the estimated cost per procedure of Gamma-Knife surgery, Gamma Knife surgery had a 30% cost advantage over surgical resection.

California↗
PubMed1996

Radiosurgery for pineal tumors: is biopsy indicated?

Pineal region tumors can be difficult to biopsy, given the critical structures in the location of the pineal gland. Modern computerized imaging techniques like computed tomography and magnetic resonance imaging used in association with tumor markers and the age at presentation may enable treatment without biopsy using a rational treatment algorithm.

Algorithms↗
PubMed1996

The open Gamma Knife Center concept.

A freestanding Gamma Knife radiosurgery center has been open for just over 1 year in La Jolla, Calif., USA, located in the grounds of a medium-sized community hospital. The center employs a full-time medical physicist and neurosurgical nurse together with clerical personnel. The neurosurgeons and radiation oncologists are drawn from the entire community and bill their fees separately. Written protocols for each indication to be treated govern patient eligibility and suggested treatment algorithms. Additionally, each patient to be treated is presented in conference, and a treatment strategy (i.e., radiosurgery, craniotomy, conventional radiation therapy) is decided. Twenty new physicians and physicists have begun training to use the Gamma Knife in the first year. Certification must be achieved before a clinician can be physician of record.

California↗
PubMed1993

Ureaplasma urealyticum in a neonatal intensive care population.

The incidence of Ureaplasma colonization at birth and its effect on the development of chronic lung disease (CLD) and on mortality was studied in a neonatal intensive care population. Ureaplasma colonization was associated with a birthweight < 1000 g (odds ratio [OR] 3.45 confidence intervals [CI] 2.13-5.60) and a gestational age < 30 weeks (OR 2.54 CI 1.71-3.79). In a case-controlled study of 112 infants, significant associations with Ureaplasma colonization were maternal pyrexia in labour (n = 38 vs 21; P = 0.015), the requirement for antibiotics in labour (n = 39 vs 16; P = 0.0005) and vaginal delivery (n = 78 vs 58; P = 0.009). Risk factors associated with the development of CLD were birthweight < 1000 g (OR 3.77 CI 2.53-5.62) and delivery by Caesarean section (OR 1.65 CI 1.11-2.43). Within the group delivered by Caesarean section. Ureaplasma colonization was also associated with an increased risk of CLD (OR 1.97 CI 1.08-3.62). Ureaplasma colonization of infants at birth is associated with factors suggestive of maternal chorioamnionitis as well as preterm birth and low birthweight. In infants delivered by Caesarean section, Ureaplasma colonization is associated with an increased risk of chronic lung disease.

Adult↗