Search PubMed⌕ Search

Biomedical subjects

L Herrera

Publications and source records attributed to L Herrera.

At least 73 records · Page 4Linked to original sources
PubMed1994

Prognostic profile in rectal cancer.

PURPOSE: The purpose of this article was to review the prognostic factors of significance in rectal cancer. METHODS: This is a retrospective review of various reports and an examination of our data. RESULTS: Current imaging techniques with endorectal ultrasound, magnetic resonance imaging with a rectal probe, and possibly tagged monoclonal antibodies allow for presurgical assessment of the invasion of the rectal wall and detection of lymph node involvement. CONCLUSIONS: Tumor penetration of the rectal wall and lymph node metastases are the most important prognostic indicators in rectal cancer and predict local and distant recurrences. When lymph node metastases occur, they are more common in small lymph nodes (< 5 mm). Patients with lymph node metastases always need to be considered for multimodality therapy. Tumors larger than or equal to T3 or with associated lymph node metastases should not be treated with sphincter-saving surgical procedures alone.

Biomarkers, Tumor↗
PubMed1994

Rochalimaea henselae infection in acquired immunodeficiency syndrome causing inflammatory disease without angiomatosis or peliosis. Demonstration by immunocytochemistry and corroboration by DNA amplification.

Rochalimaea henselae causes bacillary angiomatosis, bacillary peliosis, and persistent bacteremia. Difficult to cultivate, it is detectable in infected tissues by immunocytochemistry. This technique demonstrated R henselae in autopsy specimens obtained from three deceased patients who had acquired immunodeficiency syndrome, with pathologic tissue changes lacking neoangiogenic features. From the first patient, the cause of nodular collections of lymphocytes and nonepithelioid histiocytes in the liver, spleen, lymph nodes, bone marrow, and heart eluded detection until immunocytochemical identification of R henselae. In the second case, unexpected gross and microscopic necroinflammatory nodules in the liver and spleen contained Warthin-Starry-staining bacilli identified as R henselae immunocytochemically. The third patient was found to have pathologic changes in his liver and spleen comparable with those of the second case, as well as several other disseminated infections. In two cases, identification of R henselae was corroborated through sequencing polymerase chain reaction-amplified bacterial DNA recovered from tissue; in one case, DNA could not be amplified, possibly because of postmortem degradation. Application of the immunocytochemical technique thus has expanded the recognized spectrum of histopathologic findings associated with R henselae infection in acquired immunodeficiency syndrome, as well as proving to be potentially more sensitive than DNA amplification for this purpose when applied to autopsy tissues.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Bowel rest, intravenous hydration, and continuous high-dose infusion of octreotide acetate for the treatment of chemotherapy-induced diarrhea in patients with colorectal carcinoma.

BACKGROUND: A prospective trial was conducted involving 16 patients with colorectal adenocarcinoma using a regimen of continuous-infusion octreotide acetate (Sandostatin [octreotide acetate], Sandoz, East Hanover, NJ for the treatment of severe diarrhea induced by the weekly schedule of 5-fluorouracil (5-FU) in combination with leucovorin who were refractory to opiate therapy. METHODS: Fifteen patients had tissue-documented metastatic colorectal adenocarcinoma. An additional patient was treated adjuvantly. Fifteen patients were treated with chemotherapy consisting of 5-FU and high-dose leucovorin. The octreotide acetate regimen used was a continuous infusion of 50 micrograms/h for 12 hours followed by 100 micrograms/h for 12 hours and subsequently 150 micrograms/h for 72 hours. All patients were previous failures of diphenoxylate atropine (Lomotil diphenoxalate], Searle, Chicago, IL) given 2.5 mg orally after each loose bowel movement, but no more than 20 mg in a 24-hour period. Opiate therapy was not continued beyond 48 hours. All patients also were treated with bowel rest (nothing by mouth) and intravenous fluid hydration as well as octreotide acetate. RESULTS: Complete resolution of diarrhea was seen in 15 of 16 patients (94%). In 4 patients this was accomplished during the 100 micrograms/h infusion, and in 11 patients during the 150 micrograms/h infusion. Recurrence of diarrhea was seen in two patients after a complete cycle of octreotide acetate. Both patients were restarted at 150 micrograms/h for 72 hours of octreotide acetate with resolution of the diarrhea within 36 hours of the infusion. No toxicity related to octreotide acetate was seen in this trial. CONCLUSION: The continuous-infusion regimen of octreotide acetate 150 micrograms/h is an effective and safe schedule for the treatment of chemotherapy-induced diarrhea together with bowel rest and intravenous fluid hydration in a group of patients in whom the majority were treated with the weekly schedule of 5-FU and high-dose leucovorin.

Adenocarcinoma↗
PubMed1993

In-111 CYT-103 monoclonal antibody imaging in patients with suspected recurrent colorectal cancer.

Recurrent colorectal cancer is seen in as many as 40% of patients after curative resection. In view of the limitations of endoscopic and cross-sectional imaging, external immunoscintigraphy has been added to the follow-up regimen of patients at high-risk of recurrent disease. The authors investigated the utility of immunoscintigraphy with Indium-111 (In-111) CYT-103 (site specifically labeled conjugate of monoclonal antibody B72.3) in 19 patients with suspected recurrences after previous curative resection of colorectal carcinoma. Local or regional recurrences (4 patients) and liver metastasis (6 patients) were indicated by physical examination and computed tomography (CT), whereas nine patients had occult disease with increasing serum carcinoembryonic antigen (CEA) levels and negative conventional workups. Serum CEA levels were elevated (mean, 22 ng/ml) in all patients. Approximately 4.3 mCi In-111 labeled to 1.0 mg CYT-103 was administered intravenously to each patient. Planar and single photon emission computed tomography (SPECT) imaging were performed 2-5 days after infusion. The final diagnosis of recurrence or metastasis was established in 18 patients by second-look surgery or biopsy. One patient died before exploration. Tumor was identified at the following locations: pelvis (12 patients), abdominal wall (2 patients), retroperitoneum (1 patient), liver (5 patients), and omentum (2 patients). Superiority of monoclonal antibody (MoAb) scan is noted in the detection of pelvic and intraabdominal recurrences (100%) versus CT scan (43%). Liver metastases were identified with equal facility by both modalities. In-111 CYT-103 scan findings influenced the management of 10 (55%) of 18 patients. Surgery was avoided in one patient with disseminated metastases detected by the scan. Correct identification of occult local recurrences was made in six patients. An isolated liver metastasis was confirmed in one patient with equivocal CT scan. Finally, additional intraabdominal lesions were detected in two patients. These results suggest an important and beneficial role for In-111 CYT-103 MoAb imaging in patients with suspected recurrent colorectal carcinomas, particularly in patients in whom cross-sectional imaging is negative; such imaging may prevent patients from undergoing unnecessary surgical exploration.

Adenocarcinoma↗
PubMed1993

Limited proteolysis of Saccharomyces cerevisiae phosphoenolpyruvate carboxykinase.

Incubation of Saccharomyces cerevisiae phosphoenolpyruvate carboxykinase with trypsin under native conditions cases a time-dependent loss of activity and the production of protein fragments. Cleavage sites determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis and sequence analyses identified protease-sensitive peptide bonds between amino acid residues at positions 9-10 and 76-77. Additional fragmentation sites were also detected in a region approximately 70-80 amino acids before the carboxyl end of the protein. These results suggest that the enzyme is formed by a central compact domain comprising more than two thirds of the whole protein structure. From proteolysis experiments carried out in the presence of substrates, it could be inferred that CO2 binding specifically protects position 76-77 from trypsin action. Intrinsic fluorescence measurements demonstrated that CO2 binding induces a protein conformational change, and a dissociation constant for the enzyme CO2 complex of 8.2 +/- 0.6 mM was determined.

Amino Acid Sequence↗
PubMed1993

Nd:YAG laser as a therapeutic option in the management of gastrointestinal cancer.

We report the use of ELT utilizing an Nd:YAG laser in a group of patients with cancer who represented a significant surgical risk. Effective palliation was achieved, with minimal morbidity, and the quality of life of most of our patients was preserved or enhanced, at a minimal physiologic cost. In carefully selected patients, ELT has proved to be a safe and highly effective procedure for the management of gastrointestinal cancers. It should be considered a valuable addition to the treatment armamentarium of the practicing clinician dealing with patients with advanced cancers or patients with significant medical conditions precluding surgical resection.

Aged↗
PubMed1993

[Gestational choriocarcinoma in a tubal pregnancy].

We report a gestational choriocarcinoma arising in a tubal ectopic pregnancy. Unilateral salpingectomy and single agent methotrexate chemotherapy achieved a cure. A follow up of two years revealed no evidence of recurrence.

Adult↗
PubMed1993

Morbidity and mortality following abdominoperineal resection for rectal adenocarcinoma.

From 1979 through 1986, 56 patients, 38 males (68%) and 18 females (32%), underwent an abdominoperineal resection with a wide perineal dissection for primary adenocarcinoma of the rectum. The open perineal wounds required a mean time of 6 months to completely heal. Estimated blood loss by the surgeon ranged from 200 ml to 4200 ml with a mean of 1112 ml and a median of 1000 ml. Twenty-six patients (46%) developed postoperative or intraoperative complications. Nineteen patients (34%) underwent incidental surgery with no associated morbidity. The most commonly occurring complication was impotence in 69% of male patients. The next most common complication was bladder dysfunction with urinary retention in 14 patients (25%) and urinary incontinence in five patients (9%). There were two postoperative deaths (4%). Although the morbidity was significant, greater than 90% of the complications were treatable and resolved without major sequellae.

Abdomen↗
PubMed1992

Xenopus laevis oocyte G alpha subunits mRNAs. Detection and quantitation during oogenesis and early embryogenesis by competitive reverse PCR.

The expression of mRNAs coding for different Xenopus laevis oocyte G alpha subunits was analyzed by the PCR technique. Using the nucleotide sequences of five previously cloned cDNAs for oocyte G alpha subunits [FEBS Lett. 244, 188-192, 1989; FEBS Lett. 268, 27-31, 1990] and the highly sensitive reverse PCR reaction we found that G alpha o, G alpha i-1, G alpha i-3 and G alpha s species are present in oocyte stage VI, G alpha o mRNA being the most abundant transcript. G alpha o mRNA was further quantitated through oogenesis, unfertilized eggs and early embryogenesis stages by a competitive PCR reaction using an 'in vitro' deleted G alpha o mRNA as the internal standard. Using this approach we found that Xenopus G alpha o mRNA levels were constant during oogenesis and unfertilized eggs at a concentration of 3.5 pg of mRNA/stage (5 x 10(5) molecules) and diminish gradually during early embryogenesis, reaching a level of 0.3 pg in the gastrula stage. These findings show that oocyte G alpha o, and perhaps the rest of the alpha subunits, are expressed as maternal mRNAs and could play an important role in signal transduction at the beginning of oocyte cell differentiation.

Animals↗
PubMed1992

The utility of squamous cell carcinoma antigen for the follow-up of patients with squamous cell carcinoma of the anal canal.

BACKGROUND: Thirty-three patients with histologic documentation of squamous cell carcinoma (SCC) of the anal canal underwent prospective serial collection of 234 serum samples for radioimmunoassay of SCC tumor-associated antigen. METHODS: There were 23 female and 10 male patients, with a median age of 55 years. Twenty-two of the 33 patients had multimodality therapy with radiation therapy and chemotherapy as initial treatment. RESULTS: The median follow-up was 22 months (range, 4-52 months), with a median of 13 serum specimens per patient (range, 1-23 specimens). Twenty-eight patients currently have no evidence of disease, 4 patients are alive with disease, and 1 patient died with disease. CONCLUSION: In these 33 patients, the sensitivity of the SCC tumor-associated antigen was 76%, specificity 86%, and positive predictive value 62%.

Adult↗
PubMed1992

Expression and different polarity of aminopeptidase N in normal human colonic mucosa and colonic tumors.

Expression and cellular localization of brush-border enzymes (aminopeptidase N, dipeptidylpeptidase IV, lactase, maltase) in normal human colon, colonic polyps and malignant intestinal tumors were investigated with a panel of monoclonal antibodies reacting with either native or denatured proteins. The enzymes were detected on cryostat sections by indirect immunofluorescence staining, or affinity-purified and analyzed by gel electrophoresis and immunoblotting. Dipeptidylpeptidase IV, lactase and maltase were absent from all samples examined, while aminopeptidase N (APN) was detected at the basal membrane of the epithelial cells in most specimens of colon obtained from individuals free of intestinal tumors. In contrast, APN was frequently localized at the luminal membrane of the surface epithelium in large-intestinal mucosa distal to tumors, adenomas and hyperplastic polyps, and from members of hereditary colon cancer syndrome families. APN was also expressed in colonic tumors, where it was present in an apical cell membrane location in 3/23 adenomas and 14/35 adenocarcinomas examined. No correlation was found between tumor-cell invasiveness (classified by "Dukes" stage) and expression or cellular location of aminopeptidase N. Histologically, all positive tumors were moderately or well differentiated. These results suggest that aminopeptidase N is normally expressed in adult human colon, but epithelial cells in the large and small intestine differ in their ways of sorting this enzyme intracellularly and eventually inserting it into different aspects of their surface membrane, a process which may be altered at an early stage of carcinogenesis.

Aminopeptidases↗