Biomedical subjects

Fernando Hernandez

Publications and source records attributed to Fernando Hernandez.

6 recordsLinked to original sources

PubMed2006

Electrochemical characterization of gold stepped surfaces modified with Pd.

Three different single crystals, Au(111), Au(332), and Au(331), were used as the substrate for palladium deposition in the underpotential deposition (UPD) regime. The Au(111) single crystal was used for control experiments to compare the behavior of the vicinal surfaces. Cyclic voltammetry in 0.1 M sulfuric acid solution, as well as electrochemical impedance spectroscopy (EIS) were used to study the hydrogen adsorption on the Pd thin films. Our results suggest that the voltammetric peaks at approximately 0.3 V versus the reversible hydrogen electrode (RHE) are related to the adsorption of hydrogen at large palladium terraces, and that at least two adjacent Pd rows are needed in order for the adsorption to take place. Further cycling to more positive potentials leads to the oxidation and slow dissolution of the Pd film. The behavior of the oxidation cycles is explained in terms of a higher stability of Pd at the steps.

Journal Article↗

PubMed2005

The impact of medical issues in inpatient geriatric psychiatry.

At an advanced age, serious medical and psychiatric illnesses frequently coalesce. Often, the need for admission to inpatient geriatric psychiatric care arises from coexisting medical problems. While cognitive and behavioral interventions are important, the complexity of physical comorbidities usually becomes the focus of hospitalization and requires intensive medical treatments. This paper describes adaptations made in one metropolitan geriatric psychiatry unit in order to better treat complex patients who experience both medical and psychiatric illness. The need for all members of the interdisciplinary team to expand their practice and the importance of complementary approaches of psychiatry and medicine are emphasized.

Aged↗

PubMed2005

Laparoscopic specimen extraction: morcellation.

OBJECTIVES: To review our experience with intact extraction and morecellation of nephrectomy specimen, and the advantages and disadvantages of morcellation indicated by current reports. PATIENTS AND METHODS: In a previous study, 56 consecutive patients undergoing radical and simple transperitoneal laparoscopic nephrectomy were prospectively evaluated. Morcellation specimens (33) were extracted at the umbilical or lateral port sites and intact specimens (23) through an infraumbilical incision. Data were obtained on pathology, narcotic requirements, hospital stay, complications, estimated blood loss, size of renal mass based on preoperative imaging, specimen weight and extraction incision length. RESULTS: The mean incision length was 1.2 cm in the morcellation group and 7.1 cm in the intact group (P< 0.001). There were no significant differences in pain or recovery between the groups. In two cases of tumor nephrectomy, microscopic invasion of the perinephric adipose tissue in the intact specimen group were up-staged from clinical T1 to pT3a disease; there was no change in patient treatment based on this information. CONCLUSIONS: With proper technique, morcellation is safe for extracting renal tumours. The specimen can be evaluated for histology but not for pathological staging, limiting its use with transitional cell carcinoma. Port-site seeding is rare, and does not appear to be more frequent than with open nephrectomy. Although morcellation is cosmetically more desirable, there was no significant advantage in operating time, pain or duration of hospital stay. The choice od extraction method depends on the surgeon's preference and patient choice.

Adolescent↗

PubMed2003

Laparoscopic radical versus partial nephrectomy: assessment of complications.

PURPOSE: We evaluated the short-term morbidity and complications of laparoscopic radical nephrectomy (LRN) compared with laparoscopic partial nephrectomy (LPN). MATERIALS AND METHODS: From May 1998 to May 2002, 114 patients were identified with a single unilateral sporadic renal tumor and a normal contralateral kidney. These individuals had undergone LRN (35) or LPN (79). RESULTS: The LRN and LPN groups were analyzed for age, sex, American Society of Anesthesiologists score and body mass index. Mean tumor size in patients undergoing LRN and LPN was 2.8 +/- 1.2 (range 0.9 to 4.5) and 2.5 +/- 1.0 cm (range 1 to 4.5), respectively (p = 0.17). There were no differences between the 2 groups in terms of mean hospital stay, blood transfusion or surgical complications. There was no difference in mean preoperative and postoperative serum creatinine in patients in the LPN group. Mean postoperative serum creatinine was significantly higher than the mean preoperative level in patients in the LRN group (1.51 +/- 0.22 vs 1.18 +/- 0.37 mg/ml, range 0.6 to 2.4, p = 0.02). In each group 1 case was converted to open surgery due to bleeding. CONCLUSIONS: LPN is associated with similar postoperative convalescence and complications compared with LRN. The increase in serum creatinine noted in patients undergoing radical extirpation supports the use of LPN when clinically indicated.

Adult↗

PubMed2003

Laparoscopic nephrectomy: assessment of morcellation versus intact specimen extraction on postoperative status.

PURPOSE: We compared pathological evaluation and postoperative recovery in patients undergoing transperitoneal laparoscopic nephrectomy at our institution with morcellated vs intact specimen extraction. MATERIALS AND METHODS: A prospective evaluation of 57 consecutive patients undergoing radical and simple transperitoneal laparoscopic nephrectomy was reviewed. One patient was excluded from study due to transitional cell carcinoma, which was detected intraoperatively. The 33 morcellated specimens were extracted at the umbilical port and the 23 intact specimens were extracted through a midline infraumbilical incision. Data were obtained on narcotic requirements, hospital stay, complications, estimated blood loss, mass size based on preoperative imaging, specimen weight and extraction incision length. RESULTS: Mean incision length in the morcellated and intact specimen removal groups was 1.2 and 7.1 cm, respectively (p <0.001). No significant differences in pain or recovery were noted between the 2 groups. Two cases of microscopic invasion of the perinephric adipose tissue in the intact specimen group were up staged from clinical T1 to pT3a disease. No change in patient treatment was made based on this information. CONCLUSIONS: We did not find a significant difference in surgical time, pain or hospital stay. Only incision length was statistically significant. Postoperative recovery appeared to be similar in these 2 groups. With modern imaging modalities information on pathological stage did not alter patient treatment.

Adolescent↗

PubMed2003

Laparoscopic renal surgery after spontaneous retroperitoneal hemorrhage.

PURPOSE: We assessed the role of laparoscopic management in patients following spontaneous retroperitoneal hemorrhage from a renal tumor. MATERIALS AND METHODS: A retrospective chart review revealed 4 patients with spontaneous retroperitoneal hemorrhage treated at our institution in the last 2 years. After conservative management elsewhere patients were referred for definitive therapy. Patient characteristics and tumor size were examined and correlated with ease of surgical dissection and surgical outcome. No patient had any history of trauma. Computerized tomography was used to identify the initial extent of hemorrhage in all patients. RESULTS: All patients underwent successful laparoscopic exploration without the need for open conversion. Three patients underwent radical nephrectomy and 1 underwent laparoscopic partial nephrectomy. Renal hemorrhage extending outside of the renal capsule was associated with significantly more adhesions than renal hemorrhage confined to the renal capsule. Mean patient age was 56 years (range 36 to 70). Mean retroperitoneal tumor size was 5.3 cm (range 2.5 to 10). Three renal hematomas were extracapsular and 1 was subcapsular. Mean operative time was 182.3 minutes (range 59 to 235). Average estimated blood loss was 800 cc (range 150 to 2,100). CONCLUSIONS: Nontraumatic retroperitoneal hemorrhage of renal origin may be managed using traditional laparoscopic techniques with results similar to those achieved with open renal exploration. These cases may prove technically challenging due to fibrosis and associated tissue plane loss.

Adult↗