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Biomedical subjects

V Cohen

Publications and source records attributed to V Cohen.

At least 19 recordsLinked to original sources
PubMed2001

Effects of cocaine on the coronary arteries.

BACKGROUND: A number of studies have documented myocardial ischemia and infarction associated with cocaine use. Mismatch between myocardial oxygen supply and demand from cocaine-induced vasoconstriction and increased myocardial workload are often invoked as the major postulated mechanism by which cocaine induces myocardial ischemia. This article reviews the literature studying the effects produced by cocaine on the coronary arteries to provide insight into the various pathophysiologic mechanisms by which cocaine triggers acute cardiac ischemia or infarction. METHODS: We reviewed the published literature describing the effects of cocaine on the coronary arteries. A MEDLINE search of English language articles published between 1985 and 2000 was performed. Key words included coronary arteries, coronary vasoconstriction, vasospasm, coronary vasodilation, cardiac vasculature, myocardial ischemia, platelets, thrombosis, and cocaine. Both animal and human studies were included. The bibliographies of identified articles were also explored for additional sources of information. RESULTS: A recreational dose of cocaine increases the heart rate by approximately 30 beats/min. It also increases the blood pressure by 20/10 mm Hg. These increases are modest, are equivalent to mild exercise, and are not believed to be sufficient to result in myocardial ischemia in the majority of cases. Animal and human studies have documented cocaine-induced early coronary artery vasodilation as shown by a decrease in coronary perfusion pressure ranging from 13% to 68%. This was followed by a more sustained vasoconstriction demonstrated by a decrease in epicardial coronary artery diameter ranging from 5% to 30% with various doses of cocaine by various methods of administration. These changes alone are also an unlikely explanation for cocaine-induced myocardial ischemia. Therefore neither increases in myocardial workload nor hemodynamic changes are sufficient to explain cocaine-induced myocardial ischemia. However, evidence also exists that cocaine activates platelets and promotes thrombosis, resulting in intracoronary thrombus formation. Cocaine may also promote premature and more severe coronary atherosclerosis. CONCLUSION: The etiology of cocaine-induced myocardial ischemia is complex and is likely to be multifactorial. It appears to be the result of coronary artery vasoconstriction, intracoronary thrombosis, and accelerated atherosclerosis.

Animals↗
PubMed1999

Disease progression, adherence, and response to protease inhibitor therapy for HIV infection in an Urban Veterans Affairs Medical Center.

Indinavir therapy has demonstrated promise in the treatment of HIV-1 infection in clinical trials; however, its efficacy in a U.S. Veterans Affairs Medical Center, where access to therapy is generally unimpeded, is unknown. A review of the Miami cohort was conducted for the year beginning May 1996 to evaluate response to indinavir plus two nucleoside analogues. Of 483 HIV-1-positive patients (97% male; mean age, 46.7+/-9.7 years), 266 were offered indinavir based on their having CD4 counts <200 cells/microl or viral loads >10,000 copies/ml. Of these patients, 36% were adherent and experienced significant reductions in viral loads (-93,325+/-147,911 copies/ml) and elevations in CD4+ (111+/-103 cells/microl) and CD8+ (225+/-338 cells/microl) T cell counts. Adherent patients with baseline CD4 counts <100 cells/microl were 4.5 times more likely to have follow-up viral loads >10,000 copies/ml than those with CD4 >200 cells/microl. Adherent patients with CD4 counts <100 cells/microl did not show evidence of immune "exhaustion" because they were equal to those with CD4 counts >200 cells/microl in their capacity to replenish CD4 cells. Nonadherence to the regimen resulted in loss of therapeutic benefit and suggested that strategies to enhance adherence may become an essential component of treatment.

Adult↗
PubMed1999

Evaluation of results and treatment variables for pressure ulcers in 48 veteran spinal cord-injured patients.

This retrospective study of 48 spinal cord-injured patients with pressure ulcers seen at a tertiary referral Veterans Hospital spinal cord injury unit between 1992 and 1997 correlates a number of variables (co-morbid conditions, nutritional status, smoking history, type of repair performed, type of bed used postoperatively, ulcer location and severity, duration of postoperative antibiotic therapy, time elapsed before sitting rehabilitation began, and length of hospital stay) with ulcer repair outcome measures, including postoperative systemic and wound-healing complications, recurrence rates, and the development of new ulcers at different sites. Surgical complication rates were high, occurring in 19 patients (39.6%), and ulcer recurrence or new ulcer development occurred in 38 patients (79.2%). Correlations were found between ulcer location and postoperative wound separation and the length of hospitalization. The hospital course was shorter if the ulcer was new rather than recurrent. Other than the finding that chronic smokers had longer courses of antibiotic therapy, smoking did not correlate statistically with other outcome variables, including wound-healing complications. No significant correlations were found between any postoperative systemic or wound complications, ulcer recurrence, or new ulcer development and patient age, level of spinal cord injury, number of ulcers and grade, laboratory values, mental status, cardiac or pulmonary disease, diabetes, and presence or absence of osteomyelitis.

Adult↗
PubMed1998

Free composite myo-osseous flap with serratus anterior and rib: indications in head and neck reconstruction.

BACKGROUND: Although the microvascular transfer of the serratus/rib myo-osseous composite flap has been previously described, the indications for its use in head and neck reconstruction have not been fully explored. Slender and easily contoured, rib bone offers reconstructive advantages over other bone sources under certain circumstances. The serratus/rib myo-osseous flap can provide vascularized muscle, bone, and cartilage; in combination with the latissimus dorsi muscle, the serratus/rib flap provides additional soft-tissue bulk on a single thoracodorsal vascular pedicle unrestricted by orientation requirements of the bone. Many orientations of bone and soft tissue are possible. METHODS: We describe, through three illustrative cases, the indications for this flap, which might include bony, cartilaginous, and soft-tissue requirements in the retromolar trigone region, large calvarial defects, and large composite full-thickness cheek and mandibular defects. CONCLUSIONS: The serratus/rib composite myo-osseous flap reliably provides vascularized bone of relatively delicate composition which offers advantages in certain reconstructive circumstances. In addition, when combined with latissimus dorsi muscle on a single vascular pedicle, it supplies additional soft-tissue bulk which can be positioned without being constrained by the bone placement. Finally, this is a useful "backup" supply of vascularized bone when other sources cannot be used due to, for example, inability to use fibula in the face of severe peripheral vascular disease and inability to use iliac crest if this has been previously used as a donor site for nonvascularized free grafts (as in secondary reconstructions).

Adult↗
PubMed1998

Temporal changes in grip and pinch strength after open carpal tunnel release and the effect of ligament reconstruction.

Symptoms of pain and weakness are nearly ubiquitous after carpal tunnel release. This study investigates the length of time before restoration of grip and pinch strength after open carpal tunnel release, in a population of patients without workers' compensation-related injuries. Two different forms of carpal ligament reconstruction were carried out in 2 groups of patients, and a third group underwent no ligament reconstruction. Grip and pinch strengths were measured for participants in each group both preoperatively and at set postoperative intervals. Mean changes in strength were calculated and analysis of variance used to determine statistical significance of the changes. Grip strength at 6 weeks after surgery in the group that underwent transposition flap repair exceeded preoperative grip strength values and all 3 groups surpassed preoperative grip strength measurements at 12 weeks. By 6 weeks after surgery, all pinch measurements for 3 groups equaled or exceeded preoperative pinch measurements. The transposition flap repair group recovered faster than did the other 2 groups and surpassed those groups in maximum grip and pinch strength at 12 weeks. These results suggest that transverse carpal ligament reconstruction, particularly the transposition flap technique, after open carpal tunnel release confers a mechanical advantage and that the transverse carpal ligament is an important pulley in flexor tendon excursion.

Carpal Tunnel Syndrome↗
PubMed1998

The life span of silicone gel breast implants and a comparison of mammography, ultrasonography, and magnetic resonance imaging in detecting implant rupture: a meta-analysis.

Because of the growing concern surrounding the integrity and life span of silicone gel breast implants and the reported variations in the diagnostic accuracy of various imaging techniques in identifying ruptured implants, the authors undertook a meta-analysis of articles in the scientific literature to examine these concerns. They were able to include reports from the literature that detailed the condition and removal of 1,099 breast implants during the past 7 years. The median life span of a silicone gel implant was estimated to be 16.4 years. Of the implants, 79.1% were intact at 10 years, falling to 48.7% by 15 years. The sensitivities and specificities of three imaging modalities used in the diagnosis of implant rupture (mammography, ultrasonography, and magnetic resonance imaging [MRI]) were also evaluated and compared statistically in an effort to discover which of the three techniques might serve as the most reliable screening tool in the diagnosis of gel implant rupture. The sensitivity of mammography for finding a ruptured implant is 28.4% with a specificity of 92.9%. Ultrasonography has a sensitivity and specificity of 59.0% and 76.8% respectively compared with MRI, which was 78.1% and 80.0% respectively. For implants in place for 10 years, one would need to image 3.3 implants by ultrasound to identify a single possible rupture. However, because of the 76.8% specificity, 8.1 implants would need to be imaged to find a confirmed intraoperative rupture. This was similar to MRI, in which 3.1 implants would need to be imaged to detect one suspected rupture, and 6.1 implants would need to be imaged to find one intraoperatively confirmed rupture. The authors do not recommend either ultrasound or MRI as a screening tool based on their meta-analysis.

Breast Implants↗
PubMed1998

Division of the transverse carpal ligament and flexor tendon excursion: open and endoscopic carpal tunnel release.

Ten fresh cadaver upper extremities from 10 different subjects were used in this study of the effect of both open and endoscopic carpal tunnel release on flexor tendon excursion. The amount of excursion necessary to bring each finger from the fully extended to the fully flexed position with the fingertip just touching the palm was measured with the extremity mounted in a device that moved the wrist from extension through flexion. Endoscopic carpal tunnel release, open release, and transverse carpal ligament reconstruction were performed with tendon excursion measurements made in each of four wrist positions after each procedure. Fingertip to palm distance was also measured. The measurements of flexor tendon excursion in neutral wrist position with intact transverse carpal ligament served as the norm for each finger and as the denominator in the ratio of postoperative to preoperative excursion distances. The study confirmed the importance of the transverse carpal ligament as a flexor pulley; transection of the ligament increased the amount of flexor tendon excursion necessary to achieve finger flexion and fingertip-to-palm contact. Tendon excursion/digital flexion improved after transposition flap repair. Neither open nor endoscopic carpal tunnel release conferred any particular benefit to flexor tendon excursion postoperatively. The proximal palmar aponeurosis does not seem to have the same pulley effect as the transverse fibers of the distal palm.

Carpal Tunnel Syndrome↗
PubMed1998

Ulnar nerve entrapment at the wrist: cases from a hand surgery practice.

BACKGROUND: Eight patients with 11 instances of wrist-level ulnar nerve entrapment, a fairly uncommon compression syndrome, were identified in a hand surgery practice from 1992 through 1996. METHODS: Presentations, causes, and surgical outcomes were examined, and the pertinent literature was reviewed. RESULTS: All eight patients had extrinsic, nonidiopathic compression of the ulnar nerve caused by tumor, vascular disease, anomalous muscle development, or a tight fibrous arch at the origin of the flexor digiti minimi. In all cases, sensory symptoms resolved with removal of the cause of ulnar nerve compression. CONCLUSIONS: These cases serve to remind physicians that not every instance of numbness and tingling in the hand represents carpal tunnel syndrome. Careful clinical examination may not only localize compression of the ulnar nerve at wrist level but also may reveal its etiology. Some causes of ulnar compressive neuropathy, however, are apparent only with surgical exploration.

Carpal Tunnel Syndrome↗
PubMed1997

Ulnar nerve compression at the wrist secondary to anomalous muscles: a patient with a variant of abductor digiti minimi.

Three patients with aberrant muscles passing through Guyon's canal are described. Each of the three patients experienced, among other symptoms, dysesthesias on the volar aspects of the little and ring fingers. The anomalous muscle in two of these patients arose from the antebrachial fascia just proximal to Guyon's canal, traveled through the canal, and inserted with the abductor digiti minimi muscle. This anomaly was bilateral in both patients. In the third patient the abductor digiti minimi muscle originated radially from the transverse carpal ligament, and this variant too was bilateral. Symptoms in each of the 3 patients resolved following surgery. Ulnar nerve compression at Guyon's canal is discussed and the literature is reviewed. Although anomalous muscles occur frequently in this location, the anatomic variant found in patient 3 has not yet been described in the literature.

Adult↗
PubMed1989

[Beta-interferon for labial and genital herpes virus infection].

19 women and 9 men, aged 15-59 (mean, 35.1), who had had recurrent lip or genital infections with herpes virus (HSV) for from 1-38 years, were treated with beta-interferon gel (100,000 IU/g), self-administered 4 times daily to the affected areas. In half the patients the drug and a placebo were given in a double-blind, cross-over study. The trial lasted 30 months. Frequency of attacks, length of each attack and its severity, and the presence of itching were noted. If there was improvement in at least 2 parameters treatment was considered successful. This was the case in about 75% of the patients. The mean number of attacks per year before and during treatment with interferon was 6.8 and 3.0, respectively (p less than 0.003) and the mean length of attacks 8.2 and 4.7 days, respectively (p less than 0.001). Results of the double-blind, cross-over test were also significant, and were similar to those for the total group. These results clearly indicate that local interferon is effective treatment for genital and labial HSV infections.

Administration, Topical↗
PubMed1989

[Ambulatory anesthesia in intravenous digital angiography in children. 340 cases].

Immobility in intravenous digital angiography (ANIV) plays a leading part for high-quality results. Three hundred forty children (mean age 30 months, mean weight 12 kg) had an intravenous digital angiography in day-hospital's conditions. Intravenous general anesthesia with or without short neuromuscular blockade is able to help immobility in children. Method described requires a perfect synchronization with the radiologist. Anesthesia mean life was 6 minutes. No incident or fatal accident was observed. Many observations either confirmed the diagnosis or decided a surgical intervention. Determinant character of obtained investigations incite us to accept risks inherent in the technique.

Ambulatory Care↗
PubMed1988

Placebo-controlled trial of topical interferon in labial and genital herpes.

The efficacy of topical interferon-beta (IFN-beta) treatment was assessed in 25 patients with herpes of the lips or genitals who completed a 2-year follow-up in a double-blind placebo-controlled trial. IFN-beta gel (10(5) U/g) 4 times daily (about 2 x 10(4) U) applied locally during eruptions (about 10 days) reduced the mean number of recurrences (p less than 0.007) and the duration of eruptions (p less than 0.007): in the placebo group these indices did not change significantly. Reduction of symptoms and severity was noted in 11 of 12 patients on IFN-beta and in only 1 on placebo. No important side-effects were recorded. Topical IFN-beta may therefore be advantageous as a time-limited local treatment of recurrent herpes simplex virus infections of the genitals and lips.

Administration, Topical↗
PubMed1978

Rocky Mountain spotted fever and jaundice. Two consecutive cases acquired in Florida and a review of the literature on this complication.

Rocky mountain spotted fever is increasing in Florida, a state that has had few cases in the past. The typical clinical illness has been well described, but jaundice has been rarely reported. In two patients with illnesses resembling leptospirosis, jaundice appeared on the sixth and ninth day of illness, and peak bilirubin levels were between 7 and 9 mg/100 ml. Liver biopsy specimen from one patient showed a nonspecific hepatitis. Hemolysis and renal dysfunction may have contributed to the production of jaundice in these patients. Fourteen instances of jaundice were reported in 43 autopsied cases as of 1941, but since that time only rare mention of jaundice has been made.

Child↗
PubMed1969

Antiserum to lymphocytes and procarbazine compared as immunosuppressants in mice.

As an immunosuppressant procarbazine was as potent as an antiserum to lymphocytes in mice. Both agents significantly prolonged survivals of skin allografts by 4 to 6 weeks. At the maximum tolerated dosage, procarbazine suppressed both circulating hemagglutinins to sheep erythrocytes and plaque-forming cells in the spleen. The antiserum to lymphocytes reduced the numbers of circulating hemagglutinins and plaque-forming cells by 94 percent. Procarbazine was administered to mice for 3 weeks before their exposure to antigen. Exposure for only 9 days, commencing 48 hours before injection of sheep erythrocytes, was less effective in suppressing the titers of hemagglutinins.

Animals↗