Search PubMed⌕ Search

Biomedical subjects

R C Grekin

Publications and source records attributed to R C Grekin.

At least 37 records · Page 2Linked to original sources

Cancer of the forehead and temple regions.

Several characteristics inherent in tumors of the forehead and temple provide therapeutic challenges for the physician. These include spread along anatomic structures, a propensity toward aggressive growth patterns, the risk of nerve damage, and the preservation of important cosmetic landmarks. As a result of these problems, Mohs micrographic surgery is often indicated in the treatment of skin cancer of the forehead and temple. The high cure rates afforded by micrographic surgery, even for aggressive tumors, and tissue conservation are benefits to the patient. Although most BCCs and SCCs in this region can be handled by a dermatologic surgeon, patients may present with aggressive or neglected tumors exhibiting extensive invasion. These patients may require a cooperative approach between the dermatologic and head and neck surgeon to achieve complete tumor extirpation or appropriate reconstruction. In this article, we have tried to indicate the rationale behind the use of Mohs micrographic surgery for tumors of the forehead and temple. In selected tumors, a team approach between the micrographic and other surgeons will maximize both tumor excision and functional and cosmetic repair for the patient.

Aged↗

Genital tumors: their management by micrographic surgery.

Genital tumors represent a special group requiring effective and curative treatment while functional and cosmetic demands require tissue sparing techniques. For these reasons, micrographic surgery is indicated. Over the past 5 years we have treated 24 such patients utilizing standard techniques for micrographic surgery. The patient population included twenty male and four female patients with ages ranging from 27 to 80 years. Histologically confirmed diagnoses included squamous cell carcinoma, Bowen's disease, verrucous carcinoma, basal cell carcinoma, Paget's disease, and leiomyosarcoma. These were located on the penis, scrotum, perineum, and buttocks. Seven of these patients were considered to have recurrent tumors. Preexisting conditions existed in 6 patients, including balantis xerotica obliterans, trauma, decubitus ulcer, and hidradenitis suppurativa. All surgery was performed under local anesthesia in the cutaneous surgery unit. Average pretreatment tumor size was 2.0 X 1.9 cm. Average postoperative defect size was 4.5 X 3.7 cm. Tumors were excised with an average of three stages and 18 sections. Most defects (65%) were allowed to heal by secondary intention, five (21%) were closed primarily, and three were referred for closure. After surgery five patients developed metastases in their regional lymphatic system. No patients developed local recurrence. Micrographic surgery is a most useful treatment modality in patients with genital tumors for control of local disease. However, patients with squamous cell carcinoma should be considered for elective regional lymph node biopsy and/or dissection in conjunction with micrographically controlled excision of the primary tumor.

Adult↗

Local anesthesia in dermatologic surgery.

With the growth of dermatologic surgery the appropriate use of local anesthesia is becoming an important issue. Thoughtful use of local anesthesia can improve the patient's experience and facilitate the surgical procedure. In this review we discuss historical and pharmacologic aspects of local anesthetic agents. Emphasis is placed on clinical considerations, including contraindications, toxic reactions, and detailed descriptions of anesthetic use.

Anesthesia, Local↗

Squamous cell carcinoma of the perineum: management with Mohs' surgical excision and gluteal thigh flap.

Two patients with squamous cell carcinoma of the perineum are presented. The carcinomas were treated by wide local excision using Mohs' fresh-tissue technique for control of the surgical margins. The wounds were closed using a gluteal thigh flap. In 1 patient the flap was extended across the midline for coverage of a contralateral perineal site. Healing was complete in each case. The combination of Mohs' fresh-tissue methods and the posterior thigh flap provided accurate identification and removal of the perineal tumor with stable wound coverage.

Buttocks↗

An interdisciplinary approach to the management of basal cell carcinoma of the head and neck.

At the University of Michigan the dermatologic surgeon works closely with the head and neck surgeon in resecting extensive cutaneous malignancies that could benefit from the combined skills of both surgical specialists. Mohs surgery offers complete microscopic controlled resection of the cutaneous portion of skin cancers. Tumors extending deeply from the skin into underlying bone and soft tissue are resected with the assistance of the head and neck surgeon familiar with the anatomy and trained in the protection of the vital structures of the head and neck. It is evident that patients with large or aggressive basal cell carcinomas will best be served when this interdisciplinary approach has become commonplace.

Basal Cell Carcinoma↗

Penile tumors: their management by Mohs micrographic surgery.

Penile tumors represent a difficult group of neoplasms requiring effective and curative treatment while minimizing tissue loss to prevent cosmetic and functional deformity. Over the past 6 years, we have treated 20 patients with penile cancer utilizing the fresh tissue technique of Mohs micrographic surgery. Tumors were excised with an average of 2.25 stages. Most defects (80%) were allowed to heal by second intention. Since surgery, four patients have developed metastatic disease in their regional lymphatic system, and one patient has died from metastatic spread. One patient has developed local recurrence. Micrographic surgery is a very useful treatment modality for patients with penile tumors. Patients with SCC of the penis should be considered for elective regional lymph node biopsy and/or dissection in conjunction with micrographically controlled excision of the primary tumor.

Adult↗

Glucose and insulin responses are improved in patients with psoriasis during therapy with etretinate.

Since lipemia is commonly induced by retinoid therapy, we investigated the effects of etretinate administration on glucose metabolism by obtaining five-hour oral glucose tolerance tests in 23 patients before and after 20 weeks of etretinate therapy for psoriasis. Compared with pretreatment values, peak and aggregate levels for serum glucose and aggregate levels for serum insulin were significantly lower during therapy. The changes were not associated with obesity, weight loss during treatment, or pretherapy glucose tolerance or insulin secretion level. Of 11 patients with impaired or diabetic glucose tolerance prior to therapy, eight patients had improved glucose tolerance after 20 weeks of etretinate treatment. Despite inducing hypertriglyceridemia in most patients, etretinate therapy is associated with a reduction in glucose levels in response to a glucose load.

Adult↗

Arachidonic acid metabolites in cutaneous carcinomas. Evidence suggesting that elevated levels of prostaglandins in basal cell carcinomas are associated with an aggressive growth pattern.

There is evidence suggesting a role of eicosanoids in the growth of certain tumors. In this study, tissue samples were collected from basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs) of the skin. Both BCCs and SCCs contained more prostaglandin E2 and F2 alpha (PGE2 and PGF2 alpha) than normal epidermis. In vitro incubation of tumor samples with arachidonic acid also resulted in PGE2 and PGF2 alpha formation. Basal cell carcinomas exhibiting a histologically aggressive growth pattern contained higher levels of prostaglandins than those with a nonaggressive growth pattern, both in vivo and after in vitro incubation. Lipoxygenase products (12- and 15-hydroxyeicosatetraenoic acid) were present in smaller amounts than cyclo-oxygenase products (PGE2 and PGF2 alpha) in vivo. Compared with normal epidermis, SCCs and, particularly, BCCs produced smaller amounts of 12-hydroxyeicosatetraenoic acid during in vitro incubation with arachidonic acid. The levels of lipoxygenase products were not related to the tumor growth pattern. These results indicate that excessive prostaglandin levels in BCCs may be associated with an aggressive growth pattern.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗

The association of HLA and immune responses to bovine collagen implants.

The HLA type of patients with various kinds of immune reactions to bovine collagen implants were evaluated to determine a possible genetic basis for such responses. All patients suffering adverse clinical reactions to bovine collagen implants were lacking the HLA-DR4 antigen. All patients who received multiple bovine collagen injections without having adverse clinical reactions were lacking HLA-B5 and HLA-DR5 and had a significantly increased incidence of HLA-DR4. Combinations of histocompatibility antigens may influence immune response to bovine collagen implants.

Animals↗

Etretinate therapy for psoriasis. Reduction of antibody-dependent cell-mediated cytotoxicity of polymorphonuclear leukocytes.

We monitored the antibody-dependent cell-mediated cytotoxicity of polymorphonuclear leukocytes from 14 patients with psoriasis before and during etretinate therapy. Neutrophils obtained from the patients with psoriasis at pretherapy demonstrated significantly greater cytotoxic activity than control cells. After four weeks of etretinate therapy, the cytotoxicity of neutrophils from the psoriatic patients decreased significantly and was no longer significantly different from the control value (at a 1:1 effector-to-target ratio). The decline in neutrophil cytotoxicity preceded significant clearing of our patients' psoriasis. The reduction in the antibody-dependent cell-mediated cytotoxicity of polymorphonuclear leukocytes from patients with psoriasis occurs early during therapy and may represent one of the mechanisms of action of etretinate.

Adult↗

Etretinate therapy reduces polymorphonuclear leukocyte chemotaxis--enhancing properties of psoriatic serum.

Using a Boyden chamber technic, we measured the directed chemotaxis of polymorphonuclear leukocytes obtained from control subjects or psoriasis patients when the leukocytes were placed in sera obtained from control subjects or psoriasis patients. The samples from patients were obtained before therapy and after 2 and 4 weeks of etretinate administration. Compared with control sera, the sera from seven untreated psoriasis patients significantly enhanced the chemotaxis of polymorphonuclear leukocytes from control subjects toward a chemotaxin (p less than 0.05). After 4 weeks of etretinate therapy, the chemotaxis-stimulating ability of the sera from psoriasis patients was no longer significantly greater than that of the control sera. This decline in the chemotaxis-stimulating activity of our patients' sera preceded significant clearing of their psoriasis. The levels of circulating etretinate in the blood of our patients could not account for the reduction. Etretinate therapy had no apparent direct effect on the chemotactic activity of polymorphonuclear leukocytes from the psoriasis patients but may act in part by reducing the inflammatory effects of psoriatic sera.

Adult↗

Verrucous Bowen's disease of the plantar foot.

A patient is presented with a recurrent plantar tumor present for 15 years. This hyperkeratotic exophytic tumor behaved historically and appeared clinically to be a verrucous carcinoma. Biopsy revealed Bowen's disease. The tumor was successfully treated with Mohs surgery. The tumor is presented due to its unusual location and its appearance that closely resembled verrucous carcinoma. The Mohs technique allows for total tumor ablation with maximal preservation of tissue in this important functional area.

Aged↗

Isotretinoin for the treatment of sebaceous hyperplasia.

Two cases of diffuse multiple lesions of sebaceous hyperplasia of the face are reported. The results of both medical and surgical therapies had been unsatisfactory. The patients were treated with low dose systemic isotretinoin (13-cis-retinoic acid) which resulted in complete clearing in one case and substantial clearing in the second. We suggest that in those patients cosmetically bothered by diffuse multiple lesions of sebaceous hyperplasia, for which other therapies are unsuccessful or unamenable to the patient, isotretinoin offers a safe, rational therapeutic option.

Aged↗

Retinoid therapy is associated with excess granulation tissue responses.

In our clinical trials of isotretinoin therapy for cystic acne and etretinate treatment of psoriasis, eight patients had growth of excessive granulation tissue. The granulation tissue was found in resolving acne lesions in one patient taking isotretinoin. Among the psoriatic patients taking etretinate, the granulation tissue usually was seen adjacent to nail plates. In two patients, the side effect caused them to stop retinoid therapy. The tissue response did not appear to be related to the daily or cumulative retinoid dose.

Acne Vulgaris↗

Decreased urinary polyamines in patients with psoriasis treated with etretinate.

Oral administration of the aromatic retinoid etretinate is effective therapy for psoriasis and other epidermal hyperproliferative disorders. Since polyamine metabolism is known to be important in cell growth and differentiation, we measured urinary levels of the polyamines putrescine, spermidine, and spermine as a reflection of cutaneous polyamine metabolism in 19 psoriatic patients treated with etretinate for 16 weeks. Using thin-layer chromatography, polyamine determinations were performed on urine collected pretherapy, during therapy, and 8 weeks after therapy was concluded. Good to excellent clearing of psoriasis occurred in 18 of 19 patients. All urinary polyamines showed a downward trend in the first week of therapy, prior to significant clinical improvement. At week 16 of therapy, the greatest reduction in mean urinary polyamine content occurred. Mean putrescine levels decreased from pretherapy to week 16 by 27% (p less than 0.001), mean spermidine values fell by 34% (p less than 0.001), and mean spermine levels declined by 37% (p = 0.005). These data are consistent with the hypothesis that etretinate inhibits polyamine biosynthesis.

Adult↗

Etretinate therapy stimulates deposition of mucus-like material in epidermis of patients with psoriasis.

During therapy for psoriasis with the oral aromatic retinoid etretinate, a finely granular material was detected by electron microscopic examination of the epidermis of ten patients. Since this amorphous substance has some of the ultrastructural characteristics of mucin, it is called mucus-like material (MLM). MLM occurs occasionally in untreated psoriatic lesions; however, its deposition is enhanced by etretinate therapy. While MLM has not been fully characterized, evidence exists for the possibilities that it represents either cell products (such as mucin, or carbohydrates associated with the cell surface) or an exudate infiltrating the epidermis.

Etretinate↗