Search PubMed⌕ Search

Biomedical subjects

J R Cohen

Publications and source records attributed to J R Cohen.

At least 37 records · Page 2Linked to original sources
PubMed1998

Diagnostic failure in colonoscopies for malignant disease.

BACKGROUND: While colonoscopy has become established as more accurate than double contrast barium enema for detecting colonic polyps and cancers, as well as offering the opportunity for therapy, there are occasional instances where colonoscopy is misleading. The present study is to determine what problems occur, with a view to finding a solution. METHODS: The records of the Colorectal Project at the Princess Alexandra Hospital indicate retrospectively that 346 patients have been correctly diagnosed with cancer of the colon and rectum by colonoscopy in the 5 years up to October 1996. During the same time eight patients (2.3%) were recorded at the same hospital as being misdiagnosed by colonoscopy, the lesion being either missed completely or misplaced. RESULTS: In five of these patients there was failure to recognize that the whole colon had not been examined endoscopically, thereby missing a more proximal lesion. In two patients the lesion was missed although the entire colon was examined. In one patient the lesion was discovered but inaccurately sited. Six of these mistakes would have been obviated by the routine use of fluoroscopy to confirm the totality of the colonoscopy and to site any lesions found. The other two cases occurred because of failure to remember that colonic examination during withdrawal should be performed meticulously back as far as the anal canal. Failure to diagnose a colon cancer on the initial colonoscopy led to an average delay of 6 months for definitive care. CONCLUSIONS: It is recommended that fluoroscopy be used routinely during colonoscopy to site accurately any lesions found, and to confirm the completeness of insertion if reliable landmarks, including terminal ileum, are not clearly identified.

Aged↗
PubMed1997

A versatile microassay for elastase using succinylated elastin.

We have developed a rapid, versatile, and sensitive elastase assay that is based on the measurement of primary amines that are exposed due to enzymatic degradation of proteins, using succinylated elastin as the substrate for elastase. After incubation with elastase the degree of digestion is determined with trinitrobenzene sulfonic acid. The assay is rapid and sensitive, detecting elastase down to 1 ng/ml, and is linear up to enzyme concentrations of 10 microg/ml. The assay is carried out in microtiter plate wells and therefore offers the potential for assaying numerous samples of small volume. The use of succinylated elastin shows specificity for elastase over the control protease, trypsin. This assay is also versatile because it can be applied to samples such as cell culture supernatants, blood plasma, tissue biopsies, and tissue homogenates.

Clinical Enzyme Tests↗
PubMed1997

Effect of nitroglycerin and cerebrospinal fluid drainage on spinal cord perfusion pressure and paraplegia during aortic cross-clamping.

When sodium nitroprusside (SNP) is used to control proximal blood pressure (Px-BP) during cross-clamping (AXC) of the thoracic aorta, it decreases spinal cord perfusion pressure (SCPP) by reducing distal aortic pressure (Ds-BP) and increasing cerebrospinal fluid pressure (CSFP). The decrease cannot be reversed by CSF drainage (CSFD) because such drainage is limited by a reduction in compliance of the spinal canal. Nitroglycerin can also be used to control Px-BP, but its effect on CSF dynamics has not previously been investigated. In the present study we have compared the effects of NTG alone and in combination with CSFD, with SNP and CSFD. Each group (Gp) of six dogs was treated with SNP + CSFD (Gp 1), NTG alone (Gp 2), and NTG + CSFD (Gp 3). Left carotid and right femoral arteries were catheterized to monitor Px-BP and Ds-BP, respectively. CSFP was monitored and CSF was drained through a spinal needle placed in the cisterna cerebellomedullaris. The thoracic aorta was cross-clamped via a left thoracotomy for 60 min. Data were acquired at baseline, during aortic occlusion, and 24 hr after surgery. There were no significant differences in any measurements among the three groups before AXC; after AXC, Px-BP was maintained between 85 and 95 mm Hg in all groups. Ds-BP was significantly lower in Gp 1 than Gp 2 and 3 (7 +/- 2 mm Hg vs. 13 +/- 3 mm Hg and 17 +/- 2 mm Hg, respectively P < 0.05). CSFP did not differ between Gp 1 and 2 (10 +/- 3 mm Hg vs. 9 +/- 1 mm Hg, P > 0.05). CSFD effectively kept CSFP at zero values in Gp 3 during AXC, but not in Gp 1. SCPP was significantly higher in Gp 3 than in Gp 1 and 2 (17 +/- 2 mm Hg vs -3 +/- 4 mm Hg and 4 +/- 1 mm Hg, respectively, P < 0.05). All animals in Gp 1 and 2 suffered paraplegia, as opposed to none in Gp 3. NTG causes paraplegia by decreasing SCPP. When used in conjunction with CSFD, it controls Px-BP without causing paraplegia. CSFD cannot counteract the negative effects of SNP on SCPP; therefore, SNP contributes to postoperative paraplegia. The effects of NTG on cerebrospinal fluid dynamics are different from those of SNP. We caution surgeons against the use of NTG without CSFD during aortic cross-clamping.

Animals↗
PubMed1997

Early laparoscopic cholecystectomy for acute cholecystitis.

BACKGROUND: The timing of laparoscopic cholecystectomy for acute cholecystitis remains controversial. METHODS: One hundred ninety-four patients with acute cholecystitis were reviewed. The conversion rates for the various number of days of symptoms before surgery were analyzed. The conversion rate dramatically increased from 3.6% for those patients with 4 days of symptoms to 26% for those patients with 5 days of symptoms. The mean number of days of symptoms prior to surgery in those patients who underwent successful laparoscopic cholecystectomy was 4.1 as compared to 8.0 in those patients who required open cholecystectomy (p < 0.0001). Based on this data the patients were divided into two groups. Group 1 consisted of 109 patients who underwent laparoscopic cholecystectomy within 4 days of onset of symptoms and group 2 consisted of 85 patients who underwent laparoscopic cholecystectomy after more than 4 days following onset of symptoms. RESULTS: The conversion rate from laparoscopic to open cholecystectomy was 15%. The conversion rate for group 1 was 1.8% as compared to 31.7% for group 2 (p < 0.0001). Indications for conversion were inability to identify the anatomy secondary to inflammatory adhesions (68%), cholecystoduodenal fistula (18%), and bleeding (14%). The major complication rate for group 1 was 2.7% as compared to 13% for group 2 (p = 0.007). The mortality rate for all patients with attempted laparoscopic cholecystectomy for acute cholecystitis was 1.5%. The average procedure time for group 1 was 100 +/- 37 min vs 120 +/- 55 min in group 2. The average number of postoperative hospital days in group 1 was 5.5 +/- 2.7 days as compared to 10.8 +/- 2.7 days in group 2. CONCLUSIONS: We advocate early laparoscopic cholecystectomy within 4 days of onset of symptoms to decrease major complications and conversion rates. This decreased conversion rate results in decreased length of procedure and hospital stay.

Acute Disease↗
PubMed1997

Utility of transesophageal echocardiography and pulmonary artery catheterization during laparoscopic assisted abdominal aortic aneurysm repair.

BACKGROUND: Advanced laparoscopic procedures are more commonly performed in elderly patients with cardiac disease. There has been limited data on the use of pulmonary artery catheters (PAC) and transesophageal echocardiography (TEE) to monitor hemodynamic changes. METHODS: We prospectively studied eight patients undergoing laparoscopic assisted abdominal aortic aneurysm repair. All patients had a PAC and all but one had an intraoperative TEE. Data included heart rate (HR), temperature (temp), pulmonary artery systolic (PAS) and diastolic (PAD) pressures, mean arterial pressure (MAP), central venous pressure (CVP), pulmonary capillary wedge pressure (PCWP), cardiac index (CI), mixed venous oxygen saturation (MVO2), and oxygen extraction ratio (O2Ex) and was obtained prior to induction, during insufflation, after desufflation, during aortic cross-clamp, and at the end of the procedure. End diastolic area (EDA), a reflection of volume status, was measured on TEE. ANOVA was used for data analysis. RESULTS: No changes were noted in HR, temp, PAS, PCWP, CI, MVO2, and O2Ex. PAD and CVP were greater during insufflation compared with baseline and aortic cross-clamp without associated changes in EDA. MAP was higher at baseline compared with all other times during the procedure. CONCLUSIONS: Insufflation increased PAD and CVP. However, volume status as suggested by EDA and PCWP did not change. These data question the reliability of hemodynamic measurements obtained from the PAC during pneumoperitoneum and suggest that TEE may be sufficient for evaluation of volume status along with the added benefit of timely detection of ventricular wall motion abnormalities.

Aged↗
PubMed1997

Factors that affect the survival rate of patients with ruptured abdominal aortic aneurysms.

PURPOSE: There has been much discussion in the literature of factors that affect the mortality rate of patients who undergo repair of ruptured abdominal aortic aneurysms. Some studies have suggested restricting patient selection for repair on the basis of certain preoperative factors including age, increased creatinine level, low hemoglobin level, loss of consciousness, electrocardiographic changes, and preoperative cormorbid medical conditions. A retrospective review of 96 patients who underwent repair of a ruptured abdominal aortic aneurysm was performed to determine whether these factors would necessarily be applicable to all populations. METHODS: A retrospective chart review of all patients who underwent repair of a ruptured abdominal aortic aneurysm was performed over a study period of 20 years. Data was analyzed by both univariate and multivariate analysis. RESULTS: The mean age of the patients was 73 years. The intraoperative mortality rate was 23%. The in-hospital mortality rate was 60.4%, with a 30-day mortality rate of 56.3%. By univariate analysis of various factors associated with the mortality rate, hemoglobin level, creatinine level, lowest preoperative and average intraoperative systolic blood pressure, packed red blood cells transfused, estimated blood loss, intraoperative urine output, and temperature were statistically significant. A history of loss of consciousness was also statistically significant. No preoperative comorbid medical conditions were significant, nor was age. On a multivariate analysis, preoperative factors of loss of consciousness, a lowest preoperative systolic blood pressure less than 90 mm Hg, a hemoglobin level less than 10 g/dl, and a creatinine level greater than 1.5 mg/dl were predictive of death. The effects of the hemoglobin level, creatinine level, and loss of consciousness on the mortality rate were strongest in patients who had a lowest preoperative systolic blood pressure greater than 90 mm Hg. In patients who had the sets of preoperative factors that were associated with a 100% mortality rate, there were intraoprative factors that influenced their death. CONCLUSIONS: These findings suggest that the factors (loss of consciousness, creatinine level, hemoglobin level) that are predictive of death may be a reflection of shock in this patient population. Further studies should be directed to optimizing preoperative resuscitation. Patients who have a ruptured abdominal aortic aneurysm should not be denied therapy on the basis of any specific set of preoperative factors.

Age Factors↗
PubMed1997

Multiple idiopathic arterial aneurysms in children: a case report and review of the literature.

A 6-year-old boy from China presented initially at 2 years of age with a pulsatile mass in his right antecubital fossa. He was not fully evaluated until the age of six years, when pan-angiography and computed axial tomography scan revealed multiple aneurysms of his right brachial artery, right radial artery aneurysms, an infrarenal aortic aneurysm, and a right internal carotid artery aneurysm in the region of the cavernous sinus. The patient underwent uneventful repairs of both the abdominal aortic aneurysm and the multiple aneurysms of the right arm. Pathologic evaluation was significant for medial fibrosis of the arterial wall with decreased and disordered elastin fibers. Review of the previously reported cases in children indicate the upper extremity arteries are involved in 92% of patients, the aortoiliac region in 92% of patients, and the renal/mesenteric vessels in 77% of cases. Lower extremity and cerebrovascular arteries are involved to a lesser extent. Children with peripheral aneurysms should have pan-angiography performed before treatment is begun. Surgical repair in these cases has been excellent.

Aneurysm↗
PubMed1997

Is preoperative cardiac evaluation for abdominal aortic aneurysm repair necessary?

PURPOSE: It is reported that 25% to 50% of patients with abdominal aortic aneurysms (AAA) have severe coronary artery disease (CAD) and should undergo an aggressive cardiac workup before AAA repair. In contrast, it has been our policy that patients referred for AAA repairs undergo no cardiac testing before surgery. METHODS: This report reviews the last 113 consecutive patients who underwent elective AAA repair by the senior author using this policy. Seventy-four patients (group A) had only an electrocardiogram before surgery. The remaining 39 patients (group B) were referred having already had additional testing that included a thallium stress test (n = 20), echocardiogram (n = 18), multiple gated acquisition (MUGA) scan (n = 3), cardiac catheterization (n = 8), or some combination of these. RESULTS: There was no statistical difference between group A and group B with regard to age, sex, tobacco use or history of coronary artery disease, diabetes mellitus, stroke (CVA), hypertension, peripheral vascular disease, or chronic obstructive pulmonary disease. Group B more commonly had a history of myocardial infarction (41% vs 19%, p < 0.03) and congestive heart failure (23% vs 7%, p < 0.03). During surgery there was no significant differences in blood loss, transfusion requirements, or operative times. There were no myocardial infarctions in group A and two (5.1%) in group B, which was not significantly different. Other complications, such as CVA, renal failure, pulmonary failure, pneumonia, wound infection, and hemorrhage, were not significantly different between the two groups. Postoperative hospital stay was not significantly different. There were three deaths in the entire series (2.7%), and only one in group B was cardiac-related in a patient with known end-stage cardiac disease and a symptomatic 8 cm AAA. CONCLUSIONS: These data indicate that most patients with AAA can safely undergo repair with no cardiac workup and that cardiac workup before AAA repair contributes little information that impacts on treatment or final clinical outcome. We conclude that cardiac testing in preparation for AAA repair is not usually necessary and that intraoperative hemodynamic management may be the most important variable in determining outcome.

Aged↗
PubMed1997

Where the sun never shines: anorectal melanoma.

BACKGROUND: Melanoma occurring in the anorectal region is recognized to be an uncommon tumour with a poor prognosis. Queensland has the highest incidence rate of cutaneous melanoma in the world. The purpose of the present study was to determine if the very high incidence of cutaneous melanoma in Queensland has any bearing on the incidence of anorectal melanoma, and to compare this with published studies from other parts of the world. An assessment of the authors' results in the treatment of anorectal melanoma was made by a review of patients presenting during the last decade throughout Queensland. METHODS: All cases of melanoma occurring in Queensland are accumulated in the Melanoma Register, administered by the Queensland Melanoma Project, and data from this were used to derive the results in the present study. Queensland population data were provided by the Australian Bureau of Statistics. RESULTS: During the study period 1985-95 in Queensland there were 21,391 cases of cutaneous melanoma which occurred in an average population, during that time, of 2.89 million. During the same time there were nine cases of anorectal melanoma, giving a relative incidence therefore of 0.04%. This contrasts with published relative incidences of 0.2% for white people in North America, 11% for Southwestern Native Americans, and 14.2% for Northern Pakistan (P < 0.0001). However, the population-based incidence rates of anorectal melanoma for Queensland, United States white people, Southwestern Native Americans and Northern Pakistan are not significantly different from each other. All patients in the present series presented with large tumours, and none survived beyond 25 months despite standard surgical and adjuvant therapy. CONCLUSIONS: The protection against cutaneous melanoma afforded by skin pigmentation is not apparent in the anal area. Anorectal melanoma is no more or less frequent in Queensland, even with the very high incidence rate of cutaneous melanoma. Sun exposure appears to be neither protective nor a risk factor. The outcome of therapy for this condition remains disappointing in the authors' experience.

Adult↗
PubMed1997

Uterine metastasis from vulvar malignant melanoma. A case report.

BACKGROUND: Malignant melanoma is the second most common vulvar malignancy. The superficial inguinal lymph nodes are the main site of metastases. Endometrial metastasis of vulvar malignant melanoma has not been previously reported. CASE: Vulvar malignant melanoma was diagnosed in a 60-year-old, postmenopausal woman. Immunohistochemical stains were positive for vimentin and S-100 protein and negative for HMB-45. Six months following vulvectomy, right inguinal lymphadenectomy and immunotherapy, curettage was performed due to postmenopausal bleeding. Histologic and immunohistochemical examinations revealed metastatic malignant melanoma with the same staining reactivity as the primary vulvar neoplasm had. Hysterectomy and bilateral salpingo-oophorectomy was performed, disclosing invasion of the endometrium and the inner two thirds of the myometrium. CONCLUSION: Only 10 other cases of endometrial metastases from malignant melanoma have been previously reported. All those cases involved a primary tumor occurring in the trunk and extremities. This is presumably the first report on endometrial and myometrial metastases from vulvar malignant melanoma.

Female↗
PubMed1996

Inhibition by protease inhibitors of chemotaxis induced by elastin-derived peptides.

We studied the effect of two inhibitors of human neutrophil proteases on neutrophil chemotaxis induced by the hexapeptide Val-Gly-Val-Ala-Pro-Gly (VGVAPG), a recurring sequence in the elastin molecule. The inhibitors were tosyl-Phe chloromethyl ketone (TFCK) and N-methoxysuccinyl-Ala-Ala-Pro-Val chloromethyl ketone (MAAPVCK). We assayed chemotactic activity by the double-membrane technique in a modified Boyden chamber, after incubating the cells for 1 hr with varying concentrations of inhibitor. We observed a concentration-dependent inhibitory effect. We also measured the potency of the two chloromethyl ketones as protease inhibitors. The more potent protease inhibitor, MAAPVCK, was also the more effective in inhibiting VGVAPG-induced chemotaxis; its inhibitor dissociation constant was KI = 28 nM with elastase and KI = 33 nM with cathepsin G. For TFCK the corresponding KI values were 37 microM and 200 microM. The incubating concentration required to lower chemotaxis by half its uninhibited value was C0.5 = 0.64 microM for MAAPVCK, compared to C0.5 = 3.4 microM for TFCK. A third peptide, triglycinate (gly3), which did not inhibit the proteolytic activity of either elastase or cathepsin G, did not inhibit chemotaxis. Chemotaxis induced by formyl Met-Leu-Phe (fMLP) was weakly inhibited by both chloromethyl ketones with TFCK being somewhat more effective than MAAPVCK. We concluded that inhibition of VGVAPG-induced chemotaxis is in part specific, receptor mediated. We suggest that proteolytic inhibitors protect the extracellular matrix from degradation by inhibiting chemotaxis. Comparing the inhibitor concentrations required to half proteolytic activity with the concentration required to half chemotactic activity, we further suggest that the two functions may be of comparable significance.

Amino Acid Sequence↗
PubMed1996

Laparoscopically assisted abdominal aortic aneurysm repair. A report of 10 cases.

BACKGROUND: Laparoscopic surgery decreases postoperative pain and length of hospital stay. Whether laparoscopically assisted abdominal aortic aneurysm (AAA) repair can be safely and reliably performed is unknown. This prospective study was designed to establish the feasibility of laparoscopically assisted AAA repair and its effects on intraoperative and postoperative variables. METHODS: With IRB approval, 10 patients with infrarenal AAA requiring a tube graft underwent laparoscopically assisted AAA repair. The procedure consisted of laparoscopic dissection of the aneurysm neck and iliac vessels. Then, through an 8-11-cm minilaparotomy, a standard endoaneurysmorrhaphy was performed. Data included laparoscopic and total operative times, blood loss, fluid requirements, duration of nasogastric suction (NGT), and lengths of intensive care unit (ICU) and postoperative hospital stays. RESULTS: Laparoscopically assisted AAA was completed in nine of 10 patients. The first patient was converted to a standard incision because the aneurysm neck could not be adequately dissected. Laparoscopic and total operative times were 1.8 +/- 0.4 and 4.5 +/- 0.7 h, respectively. Mean blood loss was 1 +/- 0.6 l. Intraoperative fluid requirement was 6.6 +/- 1.3 l. The duration of NGT suction was 1.8 +/- 1.0 days. The ICU stay was 2.1 +/- 0.8 days and hospital stay was 6.7 +/- 2.5 days. There were two minor complications and no deaths. CONCLUSIONS: Laparoscopically assisted AAA repair is technically feasible with acceptable blood loss, operative time, morbidity, and mortality. Potential advantages may be early removal of the NGT and shorter ICU and hospital stays. Prospective randomized trials are needed to determine if laparoscopically assisted AAA repair is advantageous.

Aged↗
PubMed1996

Laparoscopic conservative removal of ovarian dermoid cysts.

We compared the efficacy of two dissection methods of ovarian dermoid laparoscopic cystectomy in 41 women (age 17-38 yrs) who desired future fertility. Blunt dissection and scissors were used in 21 patients (group A), and aquadissection in 20 (group B). The mean size of the cysts was comparable in both groups. The mean operating time for aquadissection was 59.3 minutes compared with 78.4 minutes for blunt dissection and scissors (p <0.05). Intraoperative spillage was significantly less common with aquadissection because with this method it is easier to avoid cyst rupture. No complication occurred with either method. Hospital stay was similar in both groups. Operative laparoscopy is a safe and effective method in the management of ovarian dermoid cysts.

Adolescent↗
PubMed1996

Effect of second-stage 0.25% epidural bupivacaine on the outcome of labor.

OBJECTIVE: To evaluate the effect of second-stage epidural bupivacaine on the outcome of labor. METHODS: Two groups of 35 patients each were randomly allocated to receive continuous epidural bupivacaine throughout labor (group 1) or until an 8-cm dilatation of the cervix (group 2). RESULTS: There was no significant difference between the 2 groups in the rates of instrument deliveries and in their Apgar scores. CONCLUSIONS: The administration of continuous epidural bupivacaine (0.25%) throughout labor and delivery does not seem to affect the outcome of labor.

Adult↗