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Biomedical subjects

V K Mehta

Publications and source records attributed to V K Mehta.

At least 19 recordsLinked to original sources
PubMed2001

Unsuspected abnormalities noted on CT treatment-planning scans obtained for breast and chest wall irradiation.

PURPOSE: Three-dimensional treatment planning and CT simulation is widely used for the treatment of a variety of cancers. At the Stanford University Medical Center, a treatment-planning CT scan is obtained before breast irradiation to optimize the dose distribution to the treated breast and to limit radiation to the opposite breast, heart, and lung. In this paper, we review the incidental findings discovered on a careful review of these scans. METHODS AND MATERIALS: Between 1997 and 1999, 153 patients referred for breast or chest wall radiation therapy underwent a treatment-planning CT scan in our department. The planning scans were extended to include not only the breast, but also the neck, thorax, and liver. A resident and attending radiation oncologist carefully reviewed each scan before approving the treatment plan. Any abnormal findings were reviewed by an attending in the department of radiology, and additional diagnostic imaging or other evaluation was obtained as necessary. RESULTS: One hundred and fifty-three sequential scans were reviewed, and 17 unsuspected abnormalities were noted (11%). The abnormalities involved the lung (n = 4), the liver (n = 3), the gallbladder (n = 4), the esophagus (n = 2), lymph nodes (n = 3), and the breast. All abnormalities were evaluated with additional imaging studies and/or appropriate consultations. Four of these abnormalities represented additional cancer foci (3%) and altered the treatment plan. CONCLUSIONS: Three-dimensional treatment-planning CT scans for breast cancer should be carefully reviewed. In our institution, 11% of these planning studies contained abnormalities, and 3% demonstrated additional unanticipated sites of involvement by breast cancer.

Breast Neoplasms↗
PubMed2001

Adjuvant chemoradiotherapy for "unfavorable" carcinoma of the ampulla of Vater: preliminary report.

HYPOTHESES: Adjuvant chemoradiotherapy decreases the risk of local recurrence in patients with adenocarcinoma of the ampulla of Vater and high-risk features. Adjuvant chemoradiotherapy for this population can be administered safely and without much morbidity. DESIGN: Controlled, prospective, single-arm study. SETTING: Tertiary care referral hospital. PATIENTS: From June 1995 to March 1999, 12 patients (7 men and 5 women; median age, 66 years; age range, 38-78 years) with "unfavorable" ampullary carcinoma were treated with adjuvant chemoradiotherapy. All patients underwent pancreaticoduodenectomy, and all pathologic findings were confirmed at Stanford University Medical Center, Stanford, Calif. Unfavorable features were defined as involved lymph nodes (n = 10), involved surgical margins (n = 1), poorly differentiated histological features (n = 3), tumor size greater than 2 cm (n = 6), or the presence of neurovascular invasion (n = 4). INTERVENTIONS: Four to 6 weeks after undergoing pylorus-preserving pancreaticoduodenectomy with regional lymphadenectomy, patients began adjuvant chemoradiotherapy consisting of concurrent radiotherapy (45 Gy) and fluorouracil by protracted venous infusion (225-250 mg/m(2) per day, 7 days per week) for 5 weeks. MAIN OUTCOME MEASURES: Local recurrence, distant recurrence, overall survival rate, and treatment-related toxic effects. RESULTS: All patients completed the prescribed treatment course. Toxic effects were assessed twice a week during treatment and graded according to the National Cancer Institute Common Toxicity Criteria Scale. One patient required a treatment interruption of 1 week for grade III nausea/vomiting. No grade IV or V toxic effects were observed. At median follow-up of 24 months (range, 13-50 months), 8 of 12 patients were alive and disease free. One patient was alive but had disease recurrence. Three patients died of this disease (liver metastases). Actuarial overall survival at 2 years was 89%, and median survival was 34 months. One surviving patient developed a local recurrence and a lung lesion. Actuarial overall survival and median survival were better than in a parallel cohort with resected high-risk pancreatic cancer (n = 26) treated with the same adjuvant chemoradiotherapy regimen (median survival, 34 vs 14 months; P<.004). CONCLUSIONS: Adjuvant chemoradiotherapy for carcinoma of the ampulla of Vater is well tolerated and might improve control of this disease in patients with unfavorable features.

Actuarial Analysis↗
PubMed2001

Radiotherapy, concomitant protracted-venous-infusion 5-fluorouracil, and surgery for ultrasound-staged T3 or T4 rectal cancer.

BACKGROUND: A prospective study was undertaken to evaluate the response and toxicity of neoadjuvant chemoradiotherapy for ultrasound-staged T3 or T4 rectal cancer. PATIENTS AND METHODS: Since 1995, 30 patients (18 males; median age, 56 (range, 25-83) years) have received preoperative chemoradiotherapy for ultrasound-staged T3 or T4 rectal cancer. All patients underwent an endorectal ultrasound, CT scan, and review in our multidisciplinary Gastrointestinal Tumor Board before treatment. All patients had pathology-demonstrated invasive adenocarcinoma of the rectum. Eleven patients were Stage T3N0, 14 were T3N1, and five were T4N1. Patients received radiotherapy to the primary tumor and draining lymph nodes (45 Gy) followed by a tumor boost (50.4-54 Gy). Protracted-venous-infusion 5-fluorouracil (225 mg/m2 per day, seven days per week) was administered throughout treatment. Surgical resection was performed six to ten weeks after completing chemoradiotherapy. Using endorectal ultrasound measurements, the primary tumor was a median of 4 (range, 0-12) cm from the anal verge, encompassed 50 (range, 20-90) percent of the rectal circumference, and was 6 (range, 3-12) cm in diameter. RESULTS: No Grade 4 toxicity was observed during chemoradiotherapy. Three patients experienced Grade 3 toxicity (diarrhea), and four patients required a treatment interruption of greater than three days. All patients completed at least 90 percent of the prescribed radiotherapy dose. All patients underwent surgical resection. Ninety-four percent had clear surgical margins. All pathologic specimens had significant evidence of necrosis, hyalinization, and fibrosis. Thirty-three percent of the specimens had a complete pathologic response (defined as no evidence of viable tumor cells). Of the 19 patients with ultrasound-staged N1 disease, only five had pathologic evidence of nodal involvement after chemoradiotherapy. Of the 25 patients with ultrasound-staged T3 disease, pathologic staging revealed eight with T0, two with T1, five with T2, and ten with T3 disease. Of the five patients with ultrasound-staged T4 disease, pathologic staging revealed two with T0, one with T2, and two with T3 disease. No patient developed progressive disease while on treatment. Two patients have experienced local failure at 6 and 20 months, and one patient failed in the liver at seven months. Twenty-seven patients remain free of disease with a median follow-up of 20 (range, 3-53) months. CONCLUSION: Our experience suggests that preoperative chemoradiotherapy is well tolerated, down-stages tumors, and sterilizes regional lymph nodes.

Adenocarcinoma↗
PubMed2001

Comparison of the CardioWest total artificial heart, the novacor left ventricular assist system and the thoratec ventricular assist system in bridge to transplantation.

BACKGROUND: Device selection has historically been supported by minimal comparative data. Since 1994, we have implanted 43 patients with the CardioWest Total Artificial Heart (CW), 23 with the Novacor Left Ventricular Assist System (N), and 26 with the Thoratec Ventricular Assist System (T). This experience provides a basis for our device selection criteria. METHODS: We reviewed retrospectively the results for survival, stroke, and infection in the CW, N, and T groups. Statistical methods included the Student's t-test, chi2 analysis, and Kaplan-Meier actuarial survival curves. RESULTS: The T group patients were younger and smaller sized than the CW or N group. The CW group had the highest mean central venous pressure (CVP) and lowest mean cardiac index. Survival to transplantation was 75% for CW, 57% for N, and 38% for T. Multiple organ failure postimplant caused most deaths in the CW and T groups. Right heart failure and stroke caused most N deaths. Linearized stroke rates (event/patient-month) were 0.03 for CW, 0.28 for N, and 0.08 for T. Serious infections were found in 20% of CW, 30% of N, and 8% of T patients, but linearized rates showed little difference and death from infection was rare. CONCLUSIONS: The N device should be used in "stable" patients with body surface area (BSA) greater than 1.7 m2 and with minimal right heart failure. Unstable patients with biventricular failure should receive a CW if the BSA is greater than 1.7 m2 or a T if they are smaller.

Adolescent↗
PubMed2001

Protracted venous infusion 5-fluorouracil with concomitant radiotherapy compared with bolus 5-fluorouracil for unresectable pancreatic cancer.

Radiation therapy (RT) with concurrent 5-fluorouracil (5-FU) administered by protracted venous infusion (PVI) replaced our prior institutional protocol of RT with bolus administration of 5-FU as standard therapy for unresectable pancreatic cancer in 1994. In this article, we compare the treatment intensity, toxicity, and outcome for patients with unresectable pancreatic cancer treated on these sequential protocols. Fifty-four patients, 27 on each protocol, with biopsy-confirmed pancreatic cancer received chemoradiotherapy. The radiotherapy field included the gross tumor volume and regional lymph nodes to a dose of 45 Gy, followed by "boost" to the gross tumor volume to 54 Gy to 60 Gy. From 1987 to 1994, patients received concurrent 5-FU administered by bolus injection, at a dose of 500 mg/m2 on days 1 to 3 and days 29 to 31 of RT. After December 1994, 5-FU was administered by PVI (200-250 mg/m2) beginning on day 1 and continuing until the completion of RT. The chemotherapy treatment intensity was increased in the group receiving 5-FU by PVI, as evidenced by an increased average weekly and cumulative dose of 5-FU (p < 0.01). The radiotherapy treatment intensity was equivalent between the two groups. The incidence of objectively quantified toxicity was not statistically different between treatment groups. Overall survival remained poor in both treatment groups. With a median follow-up of 18 months (range: 3-30 months) for surviving patients, the 6-month, 1-year, and 2-year survivals for the PVI 5-FU-treated group versus the bolus 5-FU-treated group were 56% versus 52%, 34% versus 18%, and 22% versus 13%, respectively (p = 0.9). Radiotherapy with concomitant 5-FU by PVI results in a greater weekly and total dose of chemotherapy. The method of 5-FU administration (bolus versus PVI) did not change the RT treatment intensity, experienced toxicity, or overall survival.

Adult↗
PubMed2001

Is diagnostic review of radiotherapy-planning CT scans important in the conformal therapy era?

OBJECTIVE: Detailed CT scans are often acquired during the radiotherapy planning process. This study was performed to determine the incidence of important benign and cancer-related CT findings on these scans. SUBJECTS AND METHODS: From December 1998 to December 2000, 162 radiotherapy patients who were to be treated curatively underwent treatment planning CT scans on a helical scanner in the radiology department at Washington Hospital, Fremont, CA. All CT scans were prospectively interpreted relative to diagnoses, and reports were dictated for the medical records. The diagnostic reports and records on all patients were reviewed to determine the incidence of previously unknown benign or cancer-related findings, the impacts of such findings on treatment, and the need for additional radiologic studies or procedures on the basis of the CT interpretations. RESULTS: Incidental benign findings were noted for 32 patients (20%). Potentially important benign findings were noted for three patients: two with aneurysms and one with a possible deep vein thrombosis. Potentially cancer-related findings were reported in 20 patients: a single liver lesion (four patients), multiple liver lesions (two patients), possible or probable lymphadenopathy (11 patients), abnormal soft tissue (one patient), a small-bowel obstruction (one patient), and a breast mass (one patient). After reviewing prior diagnostic studies and obtaining additional recommended studies, the physicians found that only three of the previously unknown findings required further investigation: two aneurysms, which did not require near-term treatment, and one metastatic neck node. CONCLUSION: Routine diagnostic interpretation of radiotherapy planning scans resulted in few important medical findings and changed patient care for less than 1% of the patients.

Adult↗
PubMed2000

Adjuvant radiotherapy and concomitant 5-fluorouracil by protracted venous infusion for resected pancreatic cancer.

PURPOSE: To assess the toxicity and clinical benefit from adjuvant chemoradiotherapy consisting of protracted venous infusion 5-fluorouracil (5-FU) and concomitant radiotherapy in patients with resected pancreatic cancer. METHODS AND MATERIALS: Between 1994 and 1999, 52 patients who underwent pancreaticoduodenectomy received adjuvant chemoradiotherapy. The tumor bed and regional nodes received a dose of 45 Gy in fractions of 1.8 Gy followed by boost to the tumor bed if the surgical margins were involved (total dose, 54 Gy). The patients also received concomitant 5-FU by protracted venous infusion (200-250 mg/m(2)/day, 7 days/week) during the entire radiotherapy course. RESULTS: Fifty-two patients (30 men, 22 women) were enrolled and treated on this protocol. The median age was 63 years (range, 38-78 years), and the median Karnofsky Performance Status was 80 (range, 70-100). Thirty-five percent had involved surgical margins and 59% had involved lymph nodes. All patients completed therapy, and there were no Grade IV/V toxicities observed. With median follow-up of 24 months (range, 3-52 months) for surviving patients, the median survival is 32 months, and 2-year and 3-year survivals are 62%, and 39%, respectively. CONCLUSION: Radiotherapy with concomitant 5-FU by protracted venous infusion as adjuvant treatment for resected pancreatic cancer is well tolerated. This approach allows for greater dose intensity with reduced toxicity. The median survival of this cohort of patients compares favorably with our earlier experience and other published series.

Adult↗
PubMed2000

Pancreatic tumors show high levels of hypoxia.

PURPOSE: Because of the dismal outcomes of conventional therapies for pancreatic carcinomas, we postulated that hypoxia may exist within these tumors. METHODS AND MATERIALS: Seven sequential patients with adenocarcinomas of the pancreas consented to intraoperative measurements of tumor oxygenation using the Eppendorf (Hamburg, Germany) polargraphic electrode. RESULTS: All 7 tumors demonstrated significant tumor hypoxia. In contrast, adjacent normal pancreas showed normal oxygenation. CONCLUSION: Tumor hypoxia exists within pancreatic cancers.

Aged↗
PubMed2000

Pneumothorax necessitans presenting as a presternal pneumothoracocele.

A 31-year-old woman who is an intravenous drug abuser developed sternoclavicular joint infection with mediastinal and subcutaneous tissue abscesses that communicated through an erosion in the manubrium caused by osteomyelitis. Air entrapment from a subsequent apical pneumothorax formed a localized anterior "pneumothoracocele." We referred to this condition as "pneumothorax necessitans," and we suggest including it in the differential diagnosis of anterior chest wall masses.

Abscess↗
PubMed2000

Isolation of taxoids from cell suspension cultures of Taxus wallichiana.

Cell suspension cultures of stem-derived callus of Taxus wallichiana in MS-F culture media were found to produce three C-14 oxygenated taxoids and one regular taxoid. The taxoids were identified as yunnanxane (1), 2 alpha, 5 alpha, 10 beta, 14 beta-tetraacetoxy-4(20),11-taxadiene (2), 2 alpha, 5 alpha, 10 beta-triacetoxy-14 beta-(2-methyl)-butyryloxy-4(20),11-taxadiene (3) and 1 beta-hydroxybaccatin I (4).

Alkaloids↗
PubMed2000

Successful management of an aneurysmal aortoesophageal fistula.

We report a case of aortoesophgeal fistula secondary to the aneurysm of the descending thoracic aorta. The patient presented with massive hematemesis with bright red blood. Patient was operated upon emergently and survived without complication. Six other such cases with successful outcome have been reported before, which depends on the prompt diagnosis and early surgical intervention.

Aortic Aneurysm, Thoracic↗
PubMed1999

Immune-deficient bronchiectasis associated with X-linked lymphoproliferative disease.

Bronchiectasis may occur with various congenital and acquired immunodeficiency diseases. The association of bronchiectasis and the X-linked lymphoproliferative disease (XLP), also known as Duncan's disease is unknown. We describe the case of a 39-year-old man with XLP, the oldest surviving, who developed chronic bronchiectasis with hemoptysis and required a pneumonectomy to control his symptoms.

Adult↗
PubMed1999

Surgical filariasis: immunoscreening for filarial IgG antibodies using Wuchereria bancrofti microfilarial excretory-secretory antigen.

A clinical study and immunoscreening was conducted on 363 suspected filarial patients attending the surgery out patient division of the MGIMS, Sevegram. The disease was significantly higher in males (86%) than in females (14%). Majority (52.9%) of the cases were in the age group of 11-30 years. The distribution of cases into three different grades of infection showed, 52.6%, 33.3% and 14.1% of the cases having acute (grade I), sub-acute (grade II) and chronic (grade III) stages of infection respectively. While 73% of the cases had genital manifestations, 23% were with lymphatic obstruction in limbs and the rest of the 4% suffered from manifestations like cellulitis, abscesses, haematuria and chyluria. Filarial IgG antibodies against microfilarial excretory-secretory (mf ES) antigen were detected in 89% of cases with genital manifestations, 87% of lymphoedema cases, 67% of lymphadenitis cases and 60% of cases with other clinical manifestations and 3% of endemic normals.

Adolescent↗
PubMed1994

Low-dose interleukin 1 and tumor necrosis factor individually stimulate insulin release but in combination cause suppression.

The macrophage-derived cytokines interleukin 1 (IL-1) and tumor necrosis factor (TNF) have direct effects on pancreatic beta cells and have been hypothesized to play important roles in the autoimmune beta cell lesion of type I diabetes because of two major effects on beta cells: altered insulin secretion and beta cell cytotoxicity. High doses of IL-1 are cytotoxic to beta cells and strongly inhibit insulin release; high-dose IL-1 plus TNF acts synergically to suppress further the insulin release. In contrast, we observed that the predominant effect of low-dose IL-1 and TNF when administered separately was the stimulation of insulin release. We therefore asked whether the combination of low-dose IL-1 plus TNF would act synergistically to stimulate or suppress insulin release. Studies were performed on cultured rat islets and both insulin release and cytotoxicity (51Cr release) were measured. After 2 days of culture, increasing doses of IL-1-25, 50, 75 and 100 ng/l--caused progressively increased cytotoxicity and impaired insulin release. In contrast, the lowest dose of IL-1 tested, 10 ng/l, increased insulin release but was still slightly cytotoxic. Tumor necrosis factor at doses of 10, 25, 62.5, 75 and 100 micrograms/l also was slightly cytotoxic but increased insulin release. The augmented insulin release declined progressively with increasing TNF dose. However the combination of insulin stimulatory doses of IL-1 (10 ng/l) and TNF (62.5 micrograms/l) suppressed insulin release. The effects of these two cytokines on insulin release demonstrated a similar pattern after 4 and 6 days of culture.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Intracavernous papaverine for impotence in spinal cord injured patients.

The majority of the spinal cord injury patients in our centre are young healthy males aged between 20 and 40 years. Loss of erection and inability to have coitus and father children have been responsible for inadequate sociosexual rehabilitation. In 1985, under urologist supervision, intracavernosal papaverine injection treatment was started in 101 volunteers, 65 paraplegics and 36 tetraplegics. Satisfactory erection sufficient for coital penetration was possible in 98 patients. Three had prolonged erection lasting beyond 4 hours. Only one required irrigation of the corpus with saline to achieve detumscence. One patient developed cavernosal fibrosis necessitating discontinuing the injection. Administration was under medical supervision so that possible complications of priapism/systemic effects could be promptly managed.

Adult↗
PubMed1991

Vivax malaria causing priapism.

We report a 14 year old boy who had priapism induced by vivax malaria. The onset was latent and course was protracted, refractory to anti-malarial and conservative treatment, but satisfactory detumescence was achieved after surgical intervention.

Adolescent↗
PubMed1990

Indirect haemagglutination test for the assay of antibodies against Japanese encephalitis viral antigen in human & animal sera.

The indirect haemagglutination (IHA) test was standardized for the assay of antibodies against Japanese encephalitis (JE) virus. Glutaraldehyde fixed sheep erythrocytes were sensitized with purified and concentrated JE vaccine (200-300% brain concentration). The JE vaccine made from Nakayama-NIH strain of JE virus was purified by protamine sulphate treatment and by ultracentrifugation in a sucrose gradient. The sensitized cells were quite stable in liquid as well as in lyophilized state both at -70 degrees C and 4-8 degrees C. These cells could be used for two years without much loss (4-8 times loss) in titre. The IHA test was as sensitive as the neutralization (N) test performed by plaque reduction method in chick embryo fibroblasts. The sensitivity of the test was influenced by the source of erythrocytes i.e., from the different sheep from which these were drawn. After standardization of the test, 16 human sera and 18 sera of immunized mice were assayed for antibodies against JE virus by N and IHA tests. There were no significant differences between titres of both human and mice sera determined by N and IHA tests (P greater than 0.05). The correlation coefficient between N and IHA titres for human sera was 0.60 (P less than 0.05) and for mice sera 0.82 (P less than 0.01). The IHA test has been found to be very simple, inexpensive, sensitive and reproducible.

Animals↗