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Biomedical subjects

M Gutman

Publications and source records attributed to M Gutman.

At least 127 records · Page 7Linked to original sources
PubMed1987

Nail-bed melanoma.

In our series of 348 patients treated over a 10-year period, six (1.7%) had their primary lesions in the nail bed. Five of the subungual melanomas occurred in the toes and one in the thumb. Four of the lesions were of the acral lentiginous type. The delay in diagnosis was 7 months to 6 years. Four of the patients presented with advanced, neglected tumors. One had distant metastases at diagnosis. The treatment was mainly surgical. Digital amputation was carried out for local control. Five patients underwent lymph node dissection and in three of them regional metastases were found. Of the four patients with regional and distant metastases at the time of diagnosis, three died within 6 to 60 months and the fourth is alive with metastatic spread. Of the two patients with melanoma confined to the nail bed, one is free of disease 50 months following diagnosis and the other suffered from a local recurrence and has been free of disease for 30 months following wide excision and limb perfusion.

Aged↗
PubMed1987

Surgical approach to malignant melanoma in the gastrointestinal tract.

The gastrointestinal (GI) tract is a common site for malignant melanoma. Diagnosis of lesions in the GI tract is usually delayed until complications occur, such as obstruction, bleeding, or perforation of the GI tract. Of 348 patients with malignant melanoma treated during a 10-year period, 11 had GI involvement either in a metastatic form or as a primary melanoma. Three of these patients were treated surgically for metastatic lesions in the small bowel causing intussusception, two for peritonitis secondary to perforation of the small bowel, and one for massive bleeding from metastatic melanoma in the stomach. Another patient had a primary melanoma in the esophagus and underwent esophagectomy. Three patients had primary melanomas of the anal canal and one of the rectum. Three of them underwent abdominoperineal resections, and two had bilateral groin dissection in addition. Six of the patients are alive 6 months to 4 years following diagnosis. The remaining five died of metastatic melanoma from 6 months to 4 years post-surgery.

Adult↗
PubMed1987

Gangrene of the lower limbs in diabetic patients: a malignant complication.

Diabetic foot lesions are a common medical problem with major socioeconomic impact. Gangrene is usually a late and sometimes fatal complication. A series of 118 diabetic patients who underwent amputation of the lower limb at our institution over a 10 year period has been presented. Forty-two patients underwent amputation of the toes or part of the foot, 48 underwent below-knee amputation, and 18 underwent above-knee amputation. In 24 (20.3 percent), the necrotic process advanced postoperatively and necessitated additional amputation. The average hospital stay was 33.6 days. Twenty-eight patients (23.7 percent) died during the postoperative period, and the main cause of death was sepsis. Patients who presented with extensive gangrene had a higher mortality rate. There was no correlation between mortality and the duration of conservative treatment, number of repeated operations, the treatment of diabetes before hospitalization, onset of symptoms, or status of the peripheral pulses. The solution to the problem is early and vigorous preventive treatment. This could be accomplished through highly specialized clinics within the community.

Aged↗
PubMed1987

Training aids for instruction in the initial management of injury casualties and in resuscitation procedures.

Practical experience in the initial treatment of injured patients is not easily available to the medical student. The small number of injured patients available for observation in a short time, the fact that the patients do not necessarily arrive in regular teaching hours, and the large number of students present in teaching groups compound this difficulty. Specialized instruction in these subjects is therefore important. The acquisition and use of teaching aids facilitate precise and efficient presentation of the material. We present teaching aids specifically prepared for instruction in the initial management of the injured and in resuscitation procedures. These aids include a library of video recordings documenting important emergency procedures, a TV camera used for filming these procedures, a collection of slides on the subject of emergency medicine and recent injuries, mannequins for instruction in cardiopulmonary resuscitation (CPR), utilization of the hospital's animal research laboratory for instruction in critical procedures such as venous cutdown, chest drainage, etc., and simulated computer programs.

Animals↗
PubMed1987

Interrelationship between metabolism of tritiated water, 22sodium and dry matter intake by beef cattle consuming wheat straw and poultry litter in free choice.

1. Metabolism of tritiated water and 22sodium was studied in six beef cows under Mediterranean summer conditions in order to find whether the turnover of these tracers can be used to evaluate pasture intake. 2. The diet of the cows included ad libitum access to two components which were given separately in different troughs: one was poultry litter and the other was wheat straw, to simulate the dry pasture. 3. Voluntary daily dry matter intake (111 g/kg0.75) was unexpectedly high considering the low digestibility of the feed. 4. The assumptions of constant ratios of water intake to water turnover and of dry matter intake to water intake were confirmed. Consequently, dry matter intake was determined accurately from water turnover measurements. 5. Sodium intake was practically equal to sodium turnover and most of the sodium secreted in feces was of endogenous origin. 6. Pasture intake can be predicted from sodium turnover once the concentration in feed and water consumed is known.

Animal Feed↗
PubMed1987

Rectoscopic decompression of acute recto-sigmoid obstruction.

Effective non-operative decompression of a low obstruction of the colon can sometimes be accomplished by inserting a tube into the rectum and threading the tip up to a point proximal to the obstruction (1). Failure of this non-surgical decompression would require emergency surgery--either a diverting colostomy or a two-stage resection. A new non-surgical treatment performed on a patient with an obstructive tumor of the recto-sigmoid is described. Decompression of the obstructed bowel was achieved with a rectal tube introduced over a flexible guide wire proximal to the obstruction with the aid of a rectoscope, following which a one-stage procedure--an anterior resection was performed in one patient, while the other was referred for oncological treatment.

Acute Disease↗
PubMed1987

Conventional fractionation radiotherapy combined with 5-fluorouracil for metastatic malignant melanoma.

Clinical and experimental data suggest a synergistic antitumoral effect with the combined treatment of radiotherapy and 5-fluorouracil (5-FU) serving as a radiosensitizer. This combined modality was studied in 30 malignant melanoma patients with advanced locoregional or isolated, bulky, soft-tissue or visceral metastases. All patients were symptomatic, pain being the chief complaint, followed by symptoms related to large tumors. Treatment was given on an ambulatory basis, twice weekly, and consisted of 5-FU, 500 mg/m2 administered in 8-h i.v. drip infusion, followed by radiotherapy 8 h after completion of the 5-FU administration. 60Co teleunit, delivering 400 rad per dose per fraction, was given over 6 1/2 weeks to a total of 5,200 rad. The overall response rate was 70% (21 of 30 patients). Three patients (10%) achieved a complete response lasting from 3 to 11 months, and 18 (60%) achieved a partial response lasting from 3 to 13 months. The response rate was 82% for skin, 75% for lymph node, and 43% for visceral metastases. Symptomatic relief was obtained in 83% (25 of 30) of the patients. This palliative therapy was well-tolerated, and patients were able to maintain their routine lifestyles throughout. Only in one patient was 5-FU abandoned after 3 weeks, due to cardiac ischemia. Similar response rates have only been achieved with radiotherapy alone employing individual fractions of 600 rad or higher. Since the 5-FU we added is known to have a very limited effect on malignant melanoma, this study suggests its potential as a radiosensitizer in malignant melanoma.

Abdominal Neoplasms↗
PubMed1985

Effect of buffer on kinetics of proton equilibration with a protonable group.

The laser-induced proton pulse generates a massive, brief, proton pulse capable of perturbing biochemical equilibria. The time resolution of the monitoring system can follow the diffusion-controlled protonation of specific sites on macromolecular bodies [Gutman, M. (1984) Methods Biochem. Anal. 30, 1-103]. In order to apply this method in enzymology, one must first evaluate how the buffer capacity of biochemical systems (substrates and proteins) will affect the observed dynamics. Unlike equilibrium measurements, where buffer is an inert component, in kinetic studies buffer modulates the observed dynamics. In this paper we analyze the effect of buffer on the dynamics of protonation in a model system. We describe the experimental technique and introduce the mathematical formalism that determines the various rate constants involved in the reaction. The analysis of the experiments indicates that in buffered solution proton flux is carried by two mechanisms: (A) proton dissociation followed by free proton diffusion; (B) collisional proton transfer between small diffusing solutes. We demonstrate how to evaluate the contribution of each pathway to the overall proton flux.

Arylsulfonates↗
PubMed1985

Kinetic analysis of protonation of a specific site on a buffered surface of a macromolecular body.

The kinetics of protonation of a specific site on a macromolecular structure (micelle) in buffered solution was studied with the purpose of evaluating the effect of buffer on the observed dynamics. The experimental system consisted of the following elements: Brij 58 micelles serving as homogeneous uncharged macromolecular bodies, bromocresol green, a well-adsorbed proton detector, and 2-naphthol-3,6-disulfonate as a proton emitter in the bulk. Imidazole was the mobile buffer while neutral red, which has a high affinity for the micellar surface, served as the immobile buffer. An intensive laser pulse ejects a proton from the proton emitter, and the subsequent proton-transfer reactions are measured by fast spectrophotometric methods. The dynamics of proton pulse in buffered solution are characterized by a very rapid trapping of the discharged protons by the abundant buffer molecules. This event has a major effect on the kinetic regime of the reaction. During the first 200 ns the proton flux is rate limited by free-proton diffusion. After this period, when the free-proton concentration decayed to the equilibrium level, the relaxation of the system is carried out by the diffusion of buffer. Thus in the buffered biochemical system, at neutral pH, most of proton flux between active sites and bulk is carried out by buffer molecules--not by diffusion of free protons. Surface groups on a high molecular weight body exchange protons among them at a very fast rate. This reaction has a major role on proton transfer from a specific site to the bulk.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding Sites↗
PubMed1985

Acral (volar-subungual) melanoma.

Acral melanoma occurs in the volar surface of the hands, feet, fingers, toes and subungual sites. Recently it has been recognized as a distinct entity with characteristic clinical and pathological features. Of our 340 patients with malignant melanoma, 24 (7 per cent) had acral melanoma. Sixteen were in the plantar skin, two in the palms and six in the nailbed. The delay in diagnosis was 6 months to 5 years and most of the patients presented with large neglected tumours. Fourteen lesions had histological features consistent with acral lentiginous melanoma - a unique pattern to this area. Fourteen patients were in clinical stage I at diagnosis, seven in stage II and three had distant metastases (stage III). The treatment was mainly surgical. Palmar-plantar lesions were widely excised. One patient underwent below-knee amputation. Lesions of the digits were treated by amputation of the affected toe. Fourteen of the patients underwent either prophylactic or therapeutic lymph node dissection. In 9 of them, regional metastases were found. In patients with advanced disease chemotherapy was added. Three patients had isolated limb perfusion. Fourteen patients died of metastatic disease within 1-5 years. Four are alive but have metastatic spread. Six patients are disease-free, one to 4.5 years following diagnosis.

Adult↗
PubMed1985

Effect of (+)-cyanidanol-3 on chronic active hepatitis: a double blind controlled trial.

Forty patients with biopsy proven chronic active hepatitis were studied, 22 received (+)-cyanidanol-3 in a dose of 3 g daily and 18 placebo. Side effects related to cyanidanol were fever (four patients), haemolysis (one patient) and urticaria (one patient). All side effects subsided on discontinuation of the medication. Cyanidanol had an effect no better than placebo on symptoms, laboratory tests, and histological findings on liver biopsy.

Benzopyrans↗
PubMed1984

Kinetic analysis of proton transfer between reactants adsorbed to the same micelle. The effect of proximity on the rate constants.

The dense packing of protogenic enzymes on the coupling membrane can furnish a route for a rapid proton flux which may avoid the adjacent bulk phase. In order to evaluate the role of proximity between reactants on the rate constant of proton transfer we generated a model system consisting of 2-naphthol and pH indicator (bromocresol green) both adsorbed on the same micelle of unchanged detergent. Excitation of the 2-naphthol by a short intensive laser pulse lowers its pK with subsequent synchronized proton ejection. The discharged protons are detected by their reaction with the indicator using a fast transient absorption technique. Evidence is produced that under certain conditions all of the observed proton flux represents proton transfer between 2-naphthol and indicator molecules sharing the same micelle. In this model system the entire proton flux proceeds through an aqueous phase fully accessible to phosphate ions. The high proximity of the reactants (the separation can not exceed approximately 6 nm) has a marked effect on the rate constant of the reaction k = 2.0 +/- 0.5 X 10(11) M-1 s-1. In spite of this extremely fast rate of reaction we observe unhindered competition, for the surface discharged proton, between the surface-bound reactants and phosphate ions in the bulk. Thus even in proton transfer between closely packed reactants on an interface, the diffusion of the proton is not limited to the interface. This finding implies that on bioenergetic surface the electrochemical potential of the proton on the surface will equal that of the bulk.

Adsorption↗
PubMed1984

Hypothalamic self-stimulation: the role of dopamine and possible relations to neocortical slow wave activity.

Reserpine abolishes self-stimulation in rats but the behavior can be restored temporarily by treatment with D-amphetamine or L-DOPA. Apomorphine does not restore self-stimulation even though it restores spontaneous motor activity in reserpinized rats. The data indicate that dopamine plays a role in reinforcement as well as in motor function. The ability of D-amphetamine to restore self-stimulation in reserpinized rats is eliminated by concurrent treatment with atropine or scopolamine. This effect may be related to the presence of continuous large amplitude slow wave activity in the neocortex under these conditions.

Animals↗