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Biomedical subjects

R J Rubin

Publications and source records attributed to R J Rubin.

At least 37 records · Page 2Linked to original sources
PubMed1994

Perianal hidradenitis suppurativa.

The management of hidradenitis suppurativa is individualized according to the site and extent of the disease. Initially, short-term antibiotics, local care, and incision and drainage are helpful. Unroofing of sinus tracks, total disease excision, and vigorous physical therapy are more beneficial. Primary or secondary closure or closure by an advancement flap or selective split-thickness skin grafting should be considered in some refractory cases. In most areas, recurrence rates are high unless wide excisions are performed, but perianal hidradenitis can usually be managed more conservatively. Patients with intra-anal disease are better allowed to heal secondarily than by grafting. Split-thickness grafts may contract and lead to anal stenosis, and grafts that are rejected may lead to deep scarring and anal dysfunction. The perianal region is best treated by local excision with secondary closure or by unroofing and curettage when the perianal region is more extensively involved.

Debridement↗
PubMed1994

Health care expenditures for people with diabetes mellitus, 1992.

The purpose of this report is to estimate diabetes prevalence and annual health care costs for people with diabetes in 1992, compare average annual costs for diabetics and nondiabetics, and estimate the portion of total U.S. health care expenditures incurred by people with the disease. Data from the 1987 National Medical Expenditure Survey were used to estimate diabetes prevalence and health care expenditures for diabetics in 1992. Diabetics were identified based on self-reports of a physician diagnosis of diabetes, a history of taking diabetic medications, or an encounter with the health care system specifically related to diabetes. Identified diabetics were classified as confirmed if they had a history of taking diabetic medications, had a diabetes-specific encounter with the health care system, or purchased diabetic equipment. Estimates of diabetes prevalence and health care expenditures were calculated separately for identified and confirmed diabetics using the National Medical Expenditure Survey database. Total health care expenditures included costs associated with inpatient hospital care, outpatient hospital care, office visits to a physician or other provider, emergency room visits, home health care, prescription drugs, dental care, and durable medical equipment purchases. We estimate that percapita annual health care expenditures in 1992 were more than three times greater for diabetics ($9,493) than for nondiabetics ($2,604). Percapita expenditures for confirmed diabetics ($11,157) were more than four times greater than for nondiabetics. In 1992, diabetics constituted 4.5% of the U.S. population but accounted for 14.6% of total U.S. health care expenditures ($105 billion). Confirmed diabetics constituted 3.1% of the U.S. population but accounted for 11.9% of total U.S. health care expenditures ($85 billion). This study found that health care expenditures for people with diabetes constituted about one in seven health care dollars spent in 1992. Health care reform and insurers should take note of these findings and structure benefit packages to promote care likely to reduce the costs of caring for diabetics.

Adolescent↗
PubMed1993

Is preoperative computerized tomography useful in assessing patients with colorectal carcinoma?

PURPOSE: Controversy exists over the appropriate preoperative evaluation of colorectal cancer patients. Most surgeons agree that basic laboratory studies are indicated. Computerized tomography of the abdomen and pelvis has been used in our practice to augment the preoperative evaluation of these patients. METHODS: One hundred fifty-eight consecutive patients with primary colorectal carcinoma underwent computerized tomography (CT) of the abdomen as part of their preoperative evaluation. Their medical records were retrospectively reviewed. RESULTS: In 88 patients, 120 findings present on CT were otherwise unknown. Of these, 35 percent were clinically significant in that they allowed the surgeon to alter the proposed operative procedure or added additional technical information for consideration preoperatively. Findings include liver metastasis (26), atrophic kidney (3), and abdominal wall or contiguous organ invasion (11). In addition, two other solid organ carcinomas were detected. In the remaining 70 patients, CT contributed no additional pertinent information about the patient prior to this initial operative procedure. CONCLUSIONS: CT aids in the preoperative evaluation of individuals with colorectal carcinoma. It provides important clinical information that is useful to the surgeon planning the procedure. Additionally, CT permits the patient and his family to be aware of their overall status and to subsequent treatment options. Computerized tomography eliminates the need for preoperative intravenous pyelogram, improves the preoperative staging for metastatic disease, and provides a baseline for comparison during the postoperative follow-up period should recurrence be suspected or adjuvant therapy be planned.

Adenocarcinoma↗
PubMed1993

Fluorescence dequenching kinetics of single cell-cell fusion complexes.

In an earlier paper which models the cell-cell (or virus-cell) fusion complex as two partial spherical vesicles joined at a narrow neck (Rubin, R. J., and Yi-der Chen. 1990. Biophys. J. 58:1157-1167), the redistribution by diffusion of lipid-like molecules through the neck between the two fused cell surfaces was studied. In this paper, we extend the study to the calculation of the kinetics of fluorescence increase in a single fusion complex when the lipid-like molecules are fluorescent and self-quenching. The formalism developed in this paper is useful in deducing fusion activation mechanisms from cuvette fluorescence measurements in cell-cell fusion systems. Two different procedures are presented: 1) an exact one which is based on the exact local density functions obtained from diffusion equations in our earlier study; and 2) an approximate one which is based on treating the kinetics of transfer of probes between the two fused cells as a two-state chemical reaction. For typical cell-cell fusion complexes, the fluorescence dequencing curves calculated from the exact and approximate procedures are very similar. Due to its simplicity, the approximate method should be very useful in future applications. The formalism is applied to a typical cell-cell fusion complex to study the sensitivity of dequenching curves to changes in various fusion parameters, such as the radii of the cells, the radius of the pore at the fusion junction, and the number of probes initially loaded to the complex.

Animals↗
PubMed1993

Effects of vitamin K1 and menadione on ethanol metabolism and toxicity.

The effect of administration of two exogenous quinones on in vivo ethanol metabolism and ethanol-induced toxicity has been investigated. Menadione (vitamin K3; 50 mg/kg) or vitamin K1 (250 mg/kg) were given subcutaneously (sc) to male Sprague Dawley rats 1 hour before oral administration of ethanol (4 gm/kg). Menadione, a good quinone reductase substrate, increased the elimination rate of orally administered ethanol thereby decreasing its bioavailability (as measured by the area under the curve (AUC) relating blood level to time) and its induced hepatic triglyceride accumulation. On the other hand, closely related structural analog, vitamin K1, which was proven to be a poor substrate for quinone reductase, failed to show any significant effect. Thus, these results suggest that quinone reductase appear to play a role in in vivo ethanol metabolism and toxicity.

Animals↗
PubMed1992

Arterial thromboembolic complications of inflammatory bowel disease. Report of three cases.

Extraintestinal manifestations of inflammatory bowel disease are legion and are demonstrated in one-third of those afflicted. In general, they do not mandate surgery. Three patients with active pancolonic ulcerative colitis developed arterial thromboembolic complications prior to surgical treatment. Thromboembolic complications are not fully understood, as is evidenced by the paucity of information in the literature, and only sporadic cases of arterial thromboemboli are found. These have been described primarily in the postsurgical patient. To ascertain whether others have encountered similar cases, a survey form was distributed to members of The American Society of Colon and Rectal Surgeons, yielding an additional 54 patients with thromboembolic complications. Approximately two-thirds were deep venous thromboses and/or pulmonary emboli. Ten patients had cerebrovascular accidents, and eight had arterial emboli. Eleven patients, over 21 percent, suffered multiple events. There were four resultant mortalities. An arterial thromboembolic event in a patient with ulcerative colitis is usually associated with pancolonic disease, has a poor long-term prognosis, and is an indication for colectomy.

Adult↗
PubMed1992

Computed tomography in the initial management of acute left-sided diverticulitis.

Computed tomography (CT) was used in place of contrast enemas as the initial imaging study to evaluate patients with the clinical diagnosis of acute sigmoid diverticulitis. This report attempts to clarify the role of CT in the management of acute sigmoid diverticulitis by reviewing its usefulness in the diagnosis and treatment of 59 patients. CT established that three patients (5 percent) were hospitalized with an incorrect clinical diagnosis. Thirty-seven patients (62.7 percent) were identified as having uncomplicated acute diverticulitis. These patients were all treated successfully with nonsurgical therapies and were discharged in an average of 6.8 days. In the remaining 19 patients (32.2 percent), CT revealed complicated acute diverticulitis by identifying abscess, fistula, peritonitis, or obstruction. Eleven of these 19 patients required urgent surgery or CT-guided percutaneous drainage of an abscess. The four patients whose abscesses were drained percutaneously responded favorably and underwent an elective single-stage resection. The average hospital stay for patients with complicated diverticulitis was 13.6 days. Computed tomography is a useful aid in the initial management of patients with acute diverticulitis. It is a noninvasive test that recognizes and stratifies patients according to the severity of their disease. It has the further advantage of providing information about extracolonic pathology and anatomic variation useful for surgical planning. Additionally, early CT-guided needle drainage allowed downstaging of complicated diverticulitis, avoided emergent surgery, and permitted single-stage elective surgical resection.

Abscess↗
PubMed1991

Anterior perineal sinus.

Each year we treat several patients with an anterior perineal sinus tract. They do not conform to commonly encountered perineal problems such as pilonidal disease, epidermal cysts, hidradenitis, fistulous abscess, or inflammatory bowel disease. In an effort to improve understanding of the problem and its clinical significance, we reviewed our practice records for the period from 1968 through 1988. Fifty-six patients underwent surgery for an anterior perineal sinus tract. In 31 patients, the clinical and pathologic condition defied classical diagnostic categorization. We have termed these lesions "anterior perineal sinuses." Their clinical characteristics, treatment, and pathologic assessment from the body of this report. Male predominance (87 percent) and midlife presentation (average age, 44 years) characterized this group. Local symptoms were present from several weeks to several years prior to treatment. Local anesthesia (74 percent) and limited surgery (100 percent) resulted in complete healing in all patients (average, 7 weeks). A 15 percent recurrence rate was noted. The pathologic evaluation demonstrated acute and chronic dermal and subcutaneous inflammation. The etiology of this process remains uncertain. Its predominance along the median raphe suggests a congenital midline inclusion disorder.

Adult↗
PubMed1991

Mutagenicity and metabolism of dimethyl phthalate and its binding to epidermal and hepatic macromolecules.

As an active ingredient in insect repellents, dimethyl phthalate (DMP) had previously been shown to produce chromosomal aberrations in the livers of rats following subchronic application of the phthalate to skin. When we tested DMP in the Ames mutagenesis assay, it produced in bacterial tester strain TA100 (but not TA98) a dose-related mutagenic response that was abolished by NAD- and NADP-independent metabolism associated with rat liver microsomal preparations (S9). In a host-mediated mutagenesis assay, rats were injected ip with DMP (2 g/kg body weight); urine was collected for 24 h, extracted, and analyzed for mutagenic activity and phthalic acid-containing derivatives. The extracted urine was not mutagenic to TA100 and contained an equivalent of 1.96 mg phthalate/ml urine. More than 97% of the phthalic acid-containing derivatives present in the extracted urine consisted of the nonmutagenic metabolite of DMP, monomethyl phthalate (MMP). In vitro experiments showed that rat liver homogenates hydrolyzed 93% of carbonyl-labeled 14C-DMP (7.7 mM) to MMP in 2 h and bound 0.07 nmol of [14C]phthalate/mg liver macromolecules. By contrast, rat epidermal homogenates metabolized only 5% and bound 38-fold higher levels of carbonyl-labeled 14C-DMP (2.66 nmol/mg of macromolecules), with no detectable binding to nucleic acids. Compared to epidermis and plasma, liver had a fivefold higher rate of DMP monoesterase activity (1240 nmol/h/mg protein), which, when inhibited by 67%, resulted in a 4.4-fold increase in phthalate-bound hepatic macromolecules (0.31 vs. 0.07 nmol of carbonyl-labeled 14C-DMP/mg macromolecules). In addition to MMP, formaldehyde was produced during the metabolism of DMP by liver. When ethanol was used to inhibit the oxidation of DMP-derived methanol by hepatic homogenates, there resulted a 74% reduction in the accumulation of formaldehyde and similar reductions of 71 and 73% in the binding of methyl-labeled 14C-DMP to nucleic acids and macromolecules. (Methyl-labeled, unlike carbonyl-labeled, 14C-DMP yields a 14C-labeled methanol when hydrolyzed.) These results indicate that the DMP diester is a weak bacterial mutagen, which binds to epidermal and hepatic macromolecules other than nucleic acids, and that although the rapid hepatic metabolism of DMP to its monoester (MMP) and methanol affords protection against higher levels of phthalate binding as well as against DMP-induced bacterial mutagenesis, it also oxidizes DMP-derived methanol to formaldehyde, a metabolite that binds macromolecules, including nucleic acids.

Animals↗
PubMed1990

Seton management of complex anorectal fistulas in patients with Crohn's disease.

Anorectal fistulas associated with Crohn's disease are difficult to manage, particularly when the rectum is diseased. Significant morbidity has been associated with both medical and surgical therapy. Although conventional therapy is acceptable in the management of simple fistulas in Crohn's disease, these approaches often exacerbate rather than ameliorate problems in patients with complex fistulas. The authors report ten cases of complex fistulas in patients with Crohn's disease managed with their technique of long-term, indwelling setons. These setons are placed through the fistula tract and tied loosely to maintain the patency of the fistula without cutting through the sphincters. At the time of insertion, although abscesses are incised and drained, no attempt is made to divide the superficial tissues or sphincter overlying the fistulous tract. The patients ranged in age from 23 to 81 years and had a history of Crohn's disease for 1 to 20 years. All cases resulted in excellent palliation. No patient required a proximal colostomy. These patient have been followed for four months to seven years. Despite severe proctitis in six of these patients at the initial operation, no patient has required a proctectomy. The authors believe this technique achieves adequate palliation and should be employed as the procedure of choice in patients with complex anal fistulas associated with Crohn's disease.

Adult↗