Search PubMed⌕ Search

Biomedical subjects

J M Velasco

Publications and source records attributed to J M Velasco.

At least 19 recordsLinked to original sources
PubMed2006

Prenatal diagnosis and outcome for fetuses with congenital absence of the pulmonary valve.

OBJECTIVES: To analyze fetal echocardiographic findings of absent pulmonary valve syndrome (APVS), its association with chromosomal and extracardiac anomalies including nuchal translucency (NT) and the outcome after diagnosis. METHODS: Data of 14 fetuses with confirmed APVS retrospectively collected in two tertiary referral centers between 1998 and 2004 were analyzed. The variables examined were: reason for referral, gestational age at diagnosis and associated abnormalities, including first trimester NT thickness. Cardiac evaluation included measurement of cardiothoracic ratio, diameter of pulmonary arteries and Doppler flow in the pulmonary trunk. Information was retrieved from clinical files, recorded videotapes and stored images. Karyotyping including examination for the 22q11 deletion was performed in all cases. RESULTS: Mean gestational age at diagnosis was 28 weeks, with 5/14 (36%) diagnosed before 22 weeks. In 13/14 (93%) there was an associated ventricular septal defect (subaortic in 12 fetuses and inlet-type in one) and all 13 had tetralogy of Fallot. Enlargement of the central pulmonary arteries and cardiomegaly were present in all cases diagnosed after 22 weeks. Of the five fetuses in which APVS was detected before 22 weeks, four (80%) had a normal pulmonary trunk diameter, two (40%) had normal pulmonary branches and three (60%) had normal cardiac size. The arterial duct was absent in 11/14 (79%). A correlation between presence of the arterial duct and the size of the central pulmonary arteries or cardiomegaly could not be established. Increased NT was observed in 4/10 cases (40%) for which this information was available. 22q11 microdeletion was diagnosed in three fetuses (21%). There were five terminations of pregnancy, one intrauterine death, five neonatal deaths and one infant death. Of the six neonates with respiratory distress, only one (17%) survived and of the eight babies in whom there was an intention to treat, two survived (25%). CONCLUSIONS: APVS can be accurately diagnosed by fetal echocardiography but screening ultrasound in the mid-second trimester is likely to have a low detection rate, probably due to the incomplete expression of the disease at this point. Many fetuses with APVS have an increased NT in the first trimester and this may help an earlier recognition of the defect. The most common associated karyotype anomaly is 22q11 microdeletion. Enlargement of the central pulmonary arteries is mainly related to the gestational age at diagnosis. Our results confirm that the outlook for these patients is extremely poor.

Adult↗
PubMed2006

Pulmonary balloon valvuloplasty in a fetus with critical pulmonary stenosis/atresia with intact ventricular septum and heart failure.

Outcome of fetuses with critical pulmonary stenosis (critical PS) or atresia of the pulmonary valve (PA) with intact ventricular septum (IVS) is closely related with right ventricle hypoplasia and its consequent hemodynamics. Fetal echocardiography not only allows early detection of this condition but also monitors its normally unfavorable evolution. These cases may benefit from intrauterine intervention relieving outflow tract obstruction in order to achieve a biventricular circulation. Successful valvuloplasty of the pulmonary valve was performed in a fetus with critical PS-IVS and heart failure at 25 weeks. After the procedure there was a significant improvement in fetal hemodynamics. Follow-up scans at 34 weeks detected a significant restenosis with signs of circulatory failure leading to premature delivery of the baby. An immediate postnatal valvuloplasty successfully completed the ultimate objective of biventricular repair. Fetal pulmonary valvuloplasty is feasible and may change the natural history of the disease in fetuses with critical PS-IVS.

Cardiac Output, Low↗
PubMed2001

Correlating sonography, mammography, and pathology in the assessment of breast cancer size.

BACKGROUND: With the increasing use of neoadjuvant and minimally invasive therapy, the accuracy of preoperative determination of breast tumor size becomes important. Therefore, we undertook this study to compare mammography and ultrasonography (US). METHODS: A total of 180 invasive breast cancer patients were prospectively examined by mammography and US; 146 eligible patients had tumors visualized by both modalities. RESULTS: In 69% of cases, US was better than or equivalent to mammography in determining tumor size. Both underestimated tumor size; mean (median) underestimation was 3.8 +/- 0.7 mm (1.7 mm) by US and 3.5 +/- 0.9 mm (2 mm) by mammogram. Maximal tumor dimension was accurate within 5 mm in 65% of cases by mammography and 75% of cases by US. For mammographically determined size (versus pathologic size) correlation, r, was 0.4 and for US it was 0.63 and improved for only T1 and T2 tumors. CONCLUSIONS: These data suggest that US is more accurate than mammography in assessing breast cancer size.

Adult↗
PubMed2001

Predicting the biologic behavior of ductal carcinoma in situ: an analysis of molecular markers.

BACKGROUND: Ductal carcinoma in situ (DCIS) of the breast encompasses a heterogeneous group of noninvasive cancers that now represents 19% of new breast cancer cases. Optimal treatment remains controversial. We undertook this study to characterize the relationship between angiogenic markers and the biologic behavior of various DCIS phenotypes. METHODS: We performed histopathologic review and immunohistochemistry for p53, vascular endothelial growth factor (VEGF), and factor VIII-related antigen on 103 specimens of pure DCIS. RESULTS: VEGF expression was seen in 89 tumors (86%) and correlated with microvessel density (MVD). Among VEGF-negative tumors, mean MVD (number of microvessels per square millimeter) was 48 +/- 19, versus 117 +/- 7 for tumors expressing VEGF (P =.001). Strong p53 expression was observed in 28 tumors (27%) and was associated with comedo histology, high tumor grade, necrosis, high MVD, and ipsilateral tumor recurrence (all P < or =.03). Among 8 patients with ipsilateral recurrence, 5 (63%) had tumors with strong p53 expression, whereas only 24% of patients without recurrence had tumors with strong p53 expression (P =.03). Although 7 of 8 patients with ipsilateral recurrence had tumors with VEGF and high MVD, neither parameter achieved statistical significance. CONCLUSIONS: These data suggest that molecular alterations may help predict the biologic aggressiveness of DCIS. Mutant p53 expression predisposes the patient toward ipsilateral recurrence, perhaps by promoting angiogenesis. Further investigation may identify clinically useful markers and novel treatment strategies.

Adult↗
PubMed2000

Laparoscopic ultrasound enhances diagnostic laparoscopy in the staging of intra-abdominal neoplasms.

Routine laparoscopy and laparoscopic ultrasound (LUS) for staging intra-abdominal malignancies remains controversial. Thus, we undertook a prospective study to assess the value of preoperative laparoscopy with LUS for patients with intra-abdominal tumors judged resectable by preoperative studies. Laparoscopy was successfully performed in 76 of 77 patients, and 60 underwent LUS. Of 33 patients with presumed pancreatic cancer, laparoscopic findings changed the operative management of 11 patients, and LUS altered the management of an additional 6 patients. Laparotomy was avoided in 9 patients (27%). Among 14 patients with hepatobiliary tumors, laparotomy was avoided in 9 patients in whom laparoscopy and/or LUS revealed either benign or advanced disease. Operative management was altered in 4 of 18 patients with gastric or esophageal cancer by laparoscopic findings. LUS did not add to the management of these patients. Of 12 patients with presumed intra-abdominal lymphoma, 9 were diagnosed with lymphoma and 3 with benign disease, without laparotomy in all but 1 case. Laparoscopy and LUS are valuable tools for evaluating the resectability of pancreatic and hepatobiliary tumors. Laparoscopy, and to a lesser degree LUS, greatly facilitates diagnosing patients with intra-abdominal lymphomas and spares an occasional patient with esophagogastric carcinoma from undergoing laparotomy.

Carcinoma↗
PubMed1998

A prospective analysis of office-based breast ultrasound.

OBJECTIVE: To determine the usefulness of office-based breast ultrasound. DESIGN: Prospective, nonrandomized study. SETTING: Academic-affiliated community teaching hospital. PATIENTS: Among 653 consecutive patients seen in our office during a 30-month period, we performed 660 ultrasound examinations. The presenting complaint included a palpable mass in 53%, abnormal mammogram in 39%, and nipple discharge or retraction in 3%. INTERVENTION: Ultrasound examination was performed using a handheld 7.5-MHz linear array transducer. Findings and pertinent clinicopathologic data were recorded prospectively in our Breast Ultrasound Registry. MAIN OUTCOME MEASURE: Contribution of breast ultrasound to diagnosis and treatment. RESULTS: The sonogram was normal in 201 cases (30%), showed duct ectasia in 20 cases (3%), a simple cyst or seroma in 101 cases (15%), and a focal complex or solid abnormality in 338 cases (51%). Among the last group, 114 (97%) of 118 lesions thought to be benign on ultrasonography proved to be benign, whereas 13 (12%) of 111 indeterminate and 72 (75%) of 96 sonographically suspicious lesions proved to be cancer (including 13 cases with normal mammograms). Ultrasonographic features of malignancy included an anteroposterior-to-lateral dimension ratio of 1 or greater, heterogeneous hypoechoicity, irregular shadowing, and fuzzy and/or jagged margins. Ultrasound-guided needle biopsy accurately diagnosed 46 benign nonpalpable lesions and 20 malignant nonpalpable lesions. CONCLUSIONS: These data suggest that ultrasonography is a useful adjunct to clinical and mammographic evaluation of breast disease. Breast ultrasound identifies cysts, aids in differentiating benign from malignant lesions, and facilitates office needle biopsy of nonpalpable abnormalities, permitting timely and cost-effective patient care.

Adolescent↗
PubMed1998

Postlaparoscopic small bowel obstruction. Rethinking its management.

BACKGROUND: Patients with early postoperative small bowel obstruction (SBO) are usually managed nonoperatively with nasogastric suction, intravenous fluids, and observation. The majority of early postoperative SBO resolve without an operation. METHODS: We performed a retrospective review of patients who had been diagnosed with postlaparoscopic SBO at three Chicago area teaching hospitals. RESULTS: The patients were initially managed nonoperatively for up to 7 days. However, all of them subsequently required an operation. In every case, the postlaparoscopic SBO was caused by the small bowel being incarcerated in a peritoneal defect created either by trocar placement or peritoneal incision for herniorrhaphy. CONCLUSION: In contradistinction to the approach used for early SBO after laparotomy, prompt operative intervention for postlaparoscopic SBO is recommended.

Adult↗
PubMed1998

Laparoscopic herniorrhaphy in the geriatric population.

Laparoscopy has brought controversy to herniorrhaphy, particularly in the elderly. We reviewed our experience with this technique in patients older than 65 years at a single teaching institution. Data include demographics, American Society of Anesthesiologists (ASA) class, operative time, hernia type, type of repair, hospital stay, and complications. A telephone questionnaire was used to assess return to normal activity, recurrence, and reason for choosing the laparoscopic approach. From March 1992 through March 1996, 110 of 328 patients were eligible. Mean age was 73 +/- 5.6 years; 34 patients had bilateral and 20 had recurrent hernias; 73 patients (66.4%) were ASA-2, and 22 (20%) were ASA-3. The extra-abdominal and transabdominal preperitoneal approaches were used in 64 and 46 patients, respectively; mean operative time was 87.9 +/- 34 minutes. The overall complication rate was 15 per cent, with 71 per cent of these being urinary retention. Patients were discharged the same day (59%) and at 1 day (33%). Follow-up was available in 84.5 per cent. Recurrence rate was 9.7 per cent, which was not significantly influenced by complication rate, hernia repair type, or ASA class. Median return to normal activity was 7 days. ASA classification correlated with hospital stay (P = .02), but not with complications, recurrence, or return to normal activities (P = not significant). Laparoscopic herniorrhaphy appears safe in the elderly.

Aged↗
PubMed1998

Use of ultrasound-guided fine needle aspiration biopsy in the management of thyroid disease.

Fine-needle aspiration biopsy (FNAB) of thyroid nodules has resulted in fewer patients needing thyroidectomy. Nondiagnostic FNAB specimens may require surgery for diagnosis. Ultrasound can help decrease nondiagnostic biopsies by visualizing lesions and guiding biopsy needles. Between 1996 and 1997, 76 patients had ultrasound-guided needle biopsies of thyroid nodules. Sixteen patients had clearly palpable nodules, whereas 19 were described as difficult to palpate. There were 32 patients who presented with either prominent thyroids or enlarged lobes. Six patients presented only with nonspecific symptoms, and 3 had nodules discovered incidentally on imaging studies. Biopsies were diagnostic in 73 of 76 (96%) patients. This varied with the size of the nodule, with the rate of nondiagnostic biopsies being 13 per cent in lesions <1.0 cm and 3 per cent in lesions >2.0 cm. Fifteen patients had surgery based on the FNAB, with a surgical yield of malignancy of 47 per cent. Ultrasound-guided FNAB is extremely useful in evaluating thyroid lesions that are difficult to palpate or nonpalpable, as well as the remainder of the gland and surrounding structures. The use of ultrasound guidance in performing FNAB results in a low rate of nondiagnostic biopsies, which may decrease the number of unnecessary thyroidectomies performed to rule out malignancy.

Biopsy, Needle↗
PubMed1997

Different voltage-gated sodium currents are expressed by human neuroblastoma NB69 cells when cultured in defined serum-free and in astroglial-conditioned media.

Voltage-gated Na+ currents (INa) were analysed with the whole-cell patch-clamp technique in human neuroblastoma NB69 cells plated in serum-free "defined" medium (DM) or in "astroglial-conditioned" medium (CM). Cells survived in both media and expressed the microtubule associated protein 1A, indicating neuron-like differentiation. Two INa types with different time-, voltage-dependent properties and tetrodotoxin (TTX) sensitivities were expressed in DM and CM. The INa in DM-plated cells was present from day 4 and its surface density increased from 11 pA/pF (days 5-7) to 68 pA/pF (days 15-30). The underlying conductance (GNa) half-activated (V0A) at -24 mV. INa inactivation was fitted by single exponentials with 7.5 ms time constant (th) at the -35 mV half-inactivation voltage (V0I). INa was not affected by 10 nM, was reduced (65%) by 100 nM, and not completely abolished (92%) by 300 nM tetrodotoxin (TTX). The INa of CM-plated cells appeared at day 3-4 and its surface density increased from 14 pA/pF (days 3-6) to 28 pA/pF (days 11-14). The GNa V0A was -29 mV and inactivation was fitted by single exponentials with 2.6 ms that the -58 mV V0I. This INa was reduced (55%) by 10 nM and totally abolished by 100 nM tetrodotoxin (TTX). In conclusion, NB69 cells displayed a slow, "TTX-resistant," or a fast, "TTX-sensitive" INa in DM and CM, respectively, suggesting that the CM contained diffusible trophic factors of astroglial origin that induced the expression of a different Na+ channel type. About half of the CM- and DM-plated cells also displayed a persistent Na+ current (INaP).

Action Potentials↗
PubMed1997

Differential expression of voltage-gated Ca2+ conductances in human neuroblastoma NB69 cells cultured in defined serum-free and astrocyte-conditioned media.

Voltage-gated Ca2+ conductances were investigated with the whole-cell patch-clamp technique-either using Ca2+ or Ba2+ as charge carriers-in NB69 human neuroblastoma cells plated in "defined" serum-free (DM) and in "astroglial-conditioned" media (CM). Cells expressed the microtubule associated protein 1A when plated in both media, indicating neuronlike differentiation. Cells of similar sizes and shapes were selected for recordings. Different sets of voltage-gated Ca2+ current types were usually expressed in DM- and CM-plated cells. DM-plated cells exhibited a high-voltage-activated current (HVAC) in isolation, whereas 43% of the CM-plated cells also displayed the low-voltage-activated current (LVAC). The membrane surface density of the HVAC was about twofold higher in CM than in DM-plated cells and increased with plating time from 10 and 16pA/pF (days 1-4) to 24 and 37 pA/pF (days 5-10) in DM- and CM-plated cells, respectively. However, the amplitude of the LVAC did not change significantly with culture age. In conclusion, NB69 cells expressed HVAC in isolation when plated in DM, whereas both HVAC and LVAC were present in many CM-plated cells, suggesting that the CM contained diffusible factors secreted by astroglial cells which: (1) could induce the appearance of the LVAC and (2) increased HVAC current expression.

Astrocytes↗
PubMed1996

The influence of laparoscopy on lymphocyte subpopulations in the surgical patient.

BACKGROUND: Surgical stress is known to disturb the immune system so that the overall picture is one of generalized immunosuppression proportional to the degree of stress. It has been suggested that minimally invasive procedures, i.e., laparoscopic cholecystectomy, should be accompanied by decreased surgical stress. METHODS: The present study utilized a panel of monoclonal antibodies to identify peripheral blood lymphocyte subpopulations in 11 patients scheduled for elective laparoscopic cholecystectomy. These were obtained immediately preoperatively, one day postoperatively, and one week postoperatively. RESULTS: The results demonstrated a significant (p < 0.05) decrease in T-helper to T-suppressor cell ratios the first day postoperatively compared to the preoperative ratios; the mean decrease was 13% below the preoperative ratios. There was no significant change in the ratios one week postoperatively. CONCLUSIONS: Even though laparoscopic cholecystectomy has been documented to have less disability and postoperative pain than open cholecystectomy, alterations in immune function, although attenuated, do persist.

Adult↗
PubMed1996

Preperitoneal bilateral inguinal herniorrhaphy evolution of a technique from conventional to laparoscopic.

BACKGROUND: Simultaneous repair of bilateral inguinal hernia remains controversial. METHODS: Seventy-two consecutive patients underwent a preperitoneal prosthetic repair of bilateral groin hernia; 25 via laparoscopy. ASA classification, Nyhus type, hospitalization, convalescence time, and cost were examined. Mean follow-up was 36 and 12 months for the conventional and laparoscopic group respectively. RESULTS: Sixty-nine patients were available for long-term follow-up. Average hospital stay, recurrence rate, perioperative urinary retention, transient thigh neuralgia, and return to normal activities were 48 hours, 5%, 9%, 6%, and 22 days as compared to 4 hours, 6%, 20%, 12%, and 9 days for the conventional and laparoscopic group respectively. The cost for laparoscopic repair was $500 greater. CONCLUSIONS: The preperitoneal approach to repair of bilateral hernias demonstrates an acceptable recurrence rate with low long-term morbidity. Experience with conventional preperitoneal technique greatly facilitates transition to laparoscopic repair.

Costs and Cost Analysis↗
PubMed1994

A technique for laparoscopic retraction of the acutely inflamed thick-walled gallbladder.

Utilizing the described technique, we have been able to obtain adequate cephalad retraction of the acutely inflamed, tense, and thick-walled gallbladder with minimal trauma. This has made it possible to more adequately identify key anatomical landmarks and to more safely perform the dissection in this area. We believe that the benefits of a shorter hospital stay, decreased postoperative pain, and earlier return to normal activity that patients realize when having an elective laparoscopic cholecystectomy for chronic cholecystitis can be made available as well to more patients presenting with acute cholecystitis.

Acute Disease↗
PubMed1994

Laparoscopic cholecystectomy in acute cholecystitis.

Between January 1991 and December 1992, 220 patients underwent laparoscopic cholecystectomy and were monitored prospectively. Twenty-seven patients (12.3%) had acute cholecystitis, according to strict clinical and pathologic criteria. Their average age was 60.4 years. The average operative time was 121 min. Two of the 27 patients (7.4%) required conversion to open laparotomy. The postoperative morbidity rate was 11%. The average hospital stay was 1.9 days. This series provides further evidence that laparoscopic cholecystectomy can be used safely and effectively to treat acute cholecystitis when performed by experienced surgeons.

Acute Disease↗