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Biomedical subjects

C P Clark

Publications and source records attributed to C P Clark.

At least 19 recordsLinked to original sources
PubMed2001

The effects of transdermal nicotine therapy for smoking cessation on depressive symptoms in patients with major depression.

This study examines the effects of transdermal nicotine patches for smoking cessation on depressive and withdrawal symptoms among 38 non-medicated subjects with Major Depressive Disorder. The study was conducted over a 29-day period, which included a 7 day baseline phase, a 14 day treatment phase, and an 8 day placebo phase. During the treatment phase subjects received either active nicotine patches (N = 18) or placebo patches (N = 20) that were administered in a randomized, double-blind fashion. The target quit date (TQD) was day 8. Significantly, more subjects in the placebo group than in the nicotine group resumed smoking following the TQD (50% vs. 22%). There was little evidence for effects of active nicotine patches on measures of mood (HRSD, BDI, POMS) or withdrawal symptoms among subjects that remained abstinent throughout the study (N = 24). Those who resumed smoking had more severe withdrawal symptoms than those who remained abstinent. One patient in the placebo group (n = 20) became more depressed after 2 weeks of abstinence. None of the patients in the nicotine group (n = 18) became more depressed.

Administration, Cutaneous↗
PubMed2001

Sleep deprivation, EEG, and functional MRI in depression: preliminary results.

One night of total or partial sleep deprivation (SD) produces temporary remissions in 40-60% of patients with major depression. Two unmedicated patients with major depression and a matched control received quantitative perfusion MR images at baseline and after one night of partial SD (PSD). A reduction > or =30% in the 17-item Hamilton Depression Rating Scale (omitting sleep and weight loss items) defined antidepressant response. Theory, techniques, strengths and weaknesses of quantitative perfusion MRI are described in detail. At baseline, the responder exhibited elevated perfusion covering ventral anterior cingulate/medial frontal cortex; the control's maximal perfusion area was markedly smaller. The nonresponder's perfusion was lowest of all, particularly ventrally. PSD decreased perfusion over much of the responder's hyperperfused area but did not change the nonresponder's scan. These preliminary findings are consistent with previous SD studies using PET and SPECT.

Depressive Disorder↗
PubMed2001

Fat body fructose-2,6-bisphosphate content and phosphorylase activity correlate with changes in hemolymph glucose concentration during fasting and re-feeding in larval Manduca sexta.

Fasting of second-day fifth instar larval Manduca sexta leads to a rapid decrease in hemolymph glucose concentration from 3.39+/-0.29 to 0.33+/-0.06 mM in 1 h, along with a decrease in the fructose-2,6-bisphosphate content in the fat body (from 5.92+/-0.31 to 2.80+/-0.47 nmol fructose-2,6-bisphosphate/g fat body in 3 h) and activation of fat body glycogen phosphorylase (from 16% to 55-65% phosphorylase a). During re-feeding an increase in the glucose level in the hemolymph was observed (from 0.36+/-0.05 to 3.91+/-0.36 mM in 3 h), along with an increase in the fructose-2,6-bisphosphate level in the fat body (from 2.88+/-0.47 to 6.66+/-0.42 nmol fructose-2,6-bisphosphate/g fat body in 3 h) and inactivation of fat body glycogen phosphorylase (from 56% to 16% phosphorylase a). These data are consistent with the hypothesis that a decrease in hemolymph glucose both activates fat body glycogen phosphorylase and causes a decrease in fat body fructose-2,6-bisphosphate content. Both of these changes would favor conversion of stored glucose to trehalose in the fat body. When second-day larvae were decapitated, the changes in hemolymph glucose and fat body fructose-2,6-bisphosphate were very similar to those observed in fasting whole insects. These data are consistent with a direct role for glucose in controlling carbohydrate metabolism in Manduca sexta.

Animals↗
PubMed2001

New directions in skin care.

Tretinoin and AHAs are dependable components of any skin-rejuvenation program. These products are well studied, and the results are predictable. Antioxidants make biologic sense; the initial claims were far-reaching, but there is evidence to support their use in the prevention of photoaging. Microdermabrasion has many potential applications. Epidermal level treatment is enjoying popular appeal; however, the efficacy for epidermal level treatment of photoaging has yet to be established. New products and treatments will come, and others will go. Most importantly, clinicians should remain scientists, not salespeople, in the quest for the silver bullet to combat photoaging.

Ascorbic Acid↗
PubMed1999

The rate of warping in irradiated and nonirradiated homograft rib cartilage: a controlled comparison and clinical implications.

Irradiated homograft costal cartilage reportedly warps less than autologous cartilage based on clinical observation; however, no controlled, experimental studies on the warping characteristics of irradiated homograft costal cartilage have been done. Fresh cadaver costal cartilage (ribs 5 through 8) was prepared and irradiated using a standardized technique. A specially designed cartilage-cutting device was used to cut the cartilage into a reproducible size. The irradiated (n = 23) and nonirradiated (n = 20) groups were incubated in vitro and assessed over a 4-week period. There was no significant difference in warping between the irradiated and nonirradiated groups (p = 0.1). The centrally cut pieces of cartilage in each group warped less than peripherally cut blocks in each group. Peripherally cut pieces of both the irradiated and nonirradiated groups warped at a faster rate compared with the nonirradiated groups. All cartilage exhibited continued warping over the 4-week study period. We concluded that there was no difference in warping characteristics between irradiated and nonirradiated homograft rib cartilage. Furthermore, unlike previous studies, cartilage grafts continued warping over time for at least 4 weeks, and this phenomenon may be extrapolated as a causative factor in delayed postoperative nasal deviation after rhinoplasty and nasal reconstruction where rib grafts are used.

Adult↗
PubMed1998

Increased REM sleep density at admission predicts relapse by three months in primary alcoholics with a lifetime diagnosis of secondary depression.

BACKGROUND: Having previously reported that 3-month relapse was associated with increased admission REM pressure in nondepressed primary alcoholics, we hypothesized that baseline polysomnography would predict outcome in primary alcoholics with a lifetime diagnosis of secondary depression. METHODS: Twenty-one primary alcoholics with secondary depression received polysomnography and the Hamilton Depression Rating Scale during the first and fourth weeks of a 1-month inpatient alcohol treatment program. Exclusion criteria included serious illness, current major alcohol withdrawal symptoms, other Axis I diagnoses, sleep apnea, nocturnal myoclonus, and psychoactive substances within 14 days of polysomnography. Relapse was defined as drinking any alcohol between hospital discharge and 3-month follow-up. RESULTS: Relapsers' total sleep time was reduced, and REM density (reflecting REM sleep ocular activity) was increased significantly throughout admission compared with abstainers. Sleep continuity and Hamilton scores improved by discharge in sober and relapsing alcoholics. Factors derived from admission REM latency, REM percent, and REM density predicted sobriety vs. relapse within 3 months after hospital discharge in 76% of patients. Admission REM density was greater, and total sleep time was less in relapsers than in patients sober at 3 months. CONCLUSIONS: Results suggest that increased REM density and decreased total sleep time at about 2-4 weeks of abstinence predict relapse by 3 months in depressed alcoholics.

Adult↗
PubMed1997

An anatomic study of the internal mammary veins: clinical implications for free-tissue-transfer breast reconstruction.

The anatomy of the internal mammary vessels is poorly understood and thought to be unreliable clinically for use as a recipient vein in free-tissue-transfer breast reconstruction. This study of 10 fresh cadaver thoracic cavities demonstrated by anatomic and dye resection studies that the internal mammary veins become smaller (< or = 2 mm) distally (fourth rib) and bifurcate [left (90 percent) > right (40 percent)], becoming unsuitable for consistent venous anastomoses at or below the fourth interspace. Furthermore, this study suggests that the most consistent interval is the third rib, which offers an appropriate recipient vein (40 percent > or = 3 mm on the left and 70 percent > or = 3 mm on the right). However, at the fourth interspace, 20 percent of the cadaver specimens had a vein on one side that was 1 mm or less and therefore unsuitable as a recipient. This enhanced understanding of the anatomy (size, location, and consistency) of the internal mammary recipient veins offers our patients another recipient option to enhance the safety and technical ease of microvascular breast reconstruction.

Algorithms↗
PubMed1997

Internal stabilization of autogenous rib cartilage grafts in rhinoplasty: a barrier to cartilage warping.

Autogenous rib cartilage grafts have gained more widespread use in rhinoplasty as dorsal onlay grafts and columellar struts. However, the usefulness of rib as a donor site has been limited by difficulties with postoperative cartilage warping. We hypothesized that the internal stabilization of rib cartilage grafts with Kirschner wires would prevent warping. The costochondral cartilages of a fresh cadaver were harvested and carved into 4 x 10 x 40 nm blocks. A single 0.035-in K-wire was placed longitudinally into the center of each of the study specimens (n = 9), whereas no internal stabilization was utilized in the control group (n = 9). Over a 10-day study period, a mean of 2.2 degrees of warping was observed in the grafts with K-wires as compared to 8.9 degrees in the control group. This indicates that internal stabilization of rib grafts significantly reduces warping (p < 0.001). In a subsequent clinical study, 28 patients underwent placement of internally stabilized columellar struts (n = 19) and/or dorsal nasal grafts (n = 12) using autogenous rib cartilage. At a mean follow-up of 13.5 months (range 3 to 36 months), graft warping was not observed in any patient. Satisfactory aesthetic results were achieved in all but one patient, in whom mild displacement of a dorsal onlay graft occurred. Palatal extrusion of the K-wire occurred in 3 of the first 9 columellar struts. This prompted an alteration in technique with no subsequent extrusions. We conclude that the internal stabilization of autogenous rib cartilage grafts with K-wires effectively prevents graft warpage.

Adult↗
PubMed1997

Cellular toxicity of 2,4,5-trichlorophenoxyacetic acid: formation of 2,4,5-trichlorophenoxyacetylcholine.

One of the toxic symptoms of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) is reduction in metabolic rate and subsequent growth retardation. Acetylcholine (ACh) serves as an essential growth factor to facilitate amino acid transport and to promote fetal growth. Hydatidiform mole lacks the capacity for synthesis of ACh, and inhibition of ACh synthesis depresses placental amino acid transport. Therefore, we studied the formation of 2,4,5-acetylcoenzyme A (2,4,5-T-CoA) by acetylcoenzyme A synthase (ACoAS) and the formation of 2,4,5-T-ACh by human placental choline acteyltransferase (ChA) from 2,4,5-T-CoA and choline. In these studies, the widely used analog of 2,4,5-T as an herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D), was also included. These studies have the following results (M +/- S.D.; N,6):1) The enzymatic rates of formation of acetyl-CoA, 2,4,5-T-CoA, and 2,4-D-CoA by ACoAS were 32 +/- 4, 23 +/- 3 and 26 +/- 8 nmol/mg protein/5 min., respectively; 2) There were no significant differences in the maximal amounts (nmol/mg protein) of acetyl-CoA (128 +/- 4), 2,4,5-T-CoA (125 +/- 8) and 2,4-D-CoA (96 +/- 6) formed during the reaction period of 50 min.; 3) 14C-2,4-ACh was formed from 14C-2,4-D-CoA and choline by placental-ChA; 4) Low concentrations (EC50 1-2 microM) of synthetic 2,4,5-T-ACh and 2,4-D-ACh decreased the contraction heights of the rat phrenic nerve-hemidiaphragm when the nerve or the muscle was electrically stimulated, and 5) Similar results were obtained with 2,4,6-T-ACh, an analog of 2,4,5-T-ACh. These observations indicate that chlorophenoxyherbicides form false cholinergic messengers in the nerve, muscle and placenta. These false cholinergic messengers can be formed at both muscarinic and nicotinic synaptic sites and also in non-neuronal cells, where ACh plays an important regulatory role as a local hormone, and act as blocking agents. These results will partially explain myotonia, ventricular fibrillation and fetal growth retardation induced by these herbicides.

2,4,5-Trichlorophenoxyacetic Acid↗
PubMed1996

The effect of high-dose right upper quadrant lithotripsy on normal swine tissue.

To assess the effects of high doses of shock waves to organs in the right upper quadrant of the abdomen, 36 adolescent swine were given one treatment of either 2,000 (2k), 6,000 (6k), or 10,000 (10k) shock waves at 24 kV peak pressure using a spark-gap lithotriptor. Shock waves were sonographically focused on the lumen of the gallbladder. Blood and tissue were examined for each group at 48 hours, at 35 days, and at 6 months. This study showed that administration of up to five times the accepted upper limit of shock waves produced no permanent damage. Transient injury, most commonly hematoma, was encountered. No posttreatment intra-abdominal catastrophes occurred. Although no renal injury was seen, it should be noted that the focus of maximum energy was 5 cm cephalad to the right kidney. This study suggests that an increased number of shock waves may be administered safely to this area of the abdomen.

Animals↗
PubMed1996

Alpha hydroxy acids in skin care.

Although not surgery in the traditional sense, skin care offers the ability to treat patients with a wide range of skin pathology. Skin care is another facet in facial rejuvenation, whose magnitude will increase as the pathophysiology and treatment of photoaging and other skin conditions becomes better understood. Patient satisfaction has been overwhelming for physician-directed skin care, but as the number of products, regimens, and adjuncts increase exponentially, we must emphasize a well-founded, scientific approach to the individual patient's pathology.

Acne Vulgaris↗
PubMed1995

Do differences in sleep architecture exist between depressives with comorbid simple phobia as compared with pure depressives?

Sleep records from 19 subjects with major depression and comorbid simple phobia were compared retrospectively with 25 patients with major depression alone and 25 normal controls. Groups were matched for age and gender; depressed subjects were matched for severity of depression. All subjects had been free of psychotropic medications at least 2 weeks when recorded. Sleep variables were analysed using one-way ANOVA. Both depressed groups had significantly longer sleep latency than normal controls. Depressed patients with and without simple phobia showed no differences in sleep architecture.

Depressive Disorder↗
PubMed1995

Prolactin release and clinical response to electroconvulsive therapy in depressed geriatric inpatients: a preliminary report.

Fifteen inpatients (nine women, six men) aged 50-86 years with DSM-IIIR major depression were treated with electroconvulsive therapy (ECT). Electrode placement (unilateral versus bilateral) and total number of treatments were determined by the patients' own psychiatrists according to clinical indications. Prolactin (PRL) was determined after the 1st, 6th, 7th, 9th, 11th, and final ECT treatments. Subjects were rated with the Hamilton Depression Rating Scale (HDRS) at baseline, after the sixth ECT treatment, and upon completion of ECT. PRL response to unilateral ECT was consistent across treatment for each subject. Percentage PRL increase was significantly higher for bilateral than unilateral ECT (alpha = 0.05). Subjects with final HDRS of < 12 tended to have greater peak, increase, and percentage increase PRL at the first unilateral treatment than subjects with final HDRS of at least 12; these trends approached statistical significance (Kruskal-Wallis one-way analysis of variance; peak: p = 0.059, chi = 3.556, df = 1; increase: p = 0.099, chi = 2.722, df = 1; percentage increase: p = 0.099, chi = 2.722, df = 1). Decrease in HDRS after the sixth treatment failed to show a statistically significant relationship to any PRL parameter at the initial unilateral treatment. Further studies are needed to characterize the relationship between PRL response, seizure activity, and stimulus dosing.

Aged↗
PubMed1993

Cancer in the augmented breast. Diagnosis and prognosis.

BACKGROUND: The stage of breast cancer at diagnosis in women who have undergone augmentation mammoplasty has been examined with conflicting results. Additional evaluation of this population is needed. METHODS: A retrospective review of a large cancer center's breast cancer registry for a 116-month period was performed. Comparisons of patient age, method of detection, and pathologic stage of disease at presentation were performed for 33 patients with augmented breasts and 1735 patients with nonaugmented breasts who were treated. RESULTS: Twenty-four percent of the patients with augmented breasts and 42% of those with nonaugmented breasts had mammographically detected cancers (P = NS). The incidence of ductal carcinoma in situ in the two groups was similar (18% versus 15%). Sizes of the mammographically detected tumors in the two groups were comparable; however, palpable tumors in the augmented group were significantly smaller than were those in the nonaugmented group. Overall, a significant difference in axillary lymph node involvement was detected, with 19% of the augmented group and 41% of the nonaugmented group having positive lymph nodes. In patients with palpable tumors, axillary lymph node involvement also was significantly different, with 22% of the patients with augmented breasts and 58% of those with nonaugmented breasts having axillary lymph node metastases. In the mammographically detected tumors, there was no significant difference in axillary lymph node metastases between the patients with augmented (13%) and those with nonaugmented (15%) breasts. CONCLUSIONS: Early detection of breast cancer is possible in the patient who has undergone augumentation mammoplasty. Mammography was successful in detecting occult lesions, and palpation detected smaller tumors. In this cohort, there was no evidence to suggest that the patients with augmented breasts had more advanced disease at presentation.

Adult↗
PubMed1993

Controversy over the silicone gel breast implant: current status and clinical implications.

The silicone gel breast implant controversy has generated much confusion, making informed decision making for physicians and patients increasingly difficult. In order to better understand the controversy, we review the steps taken by the Food and Drug Administration and the resultant status of breast implants. The currently available scientific data are summarized with regard to cancer development and detection, implant rupture and gel migration, and autoimmune disorders. By reviewing the presently available information on silicone gel breast implants, we can better address the concerns of our patients.

Breast↗
PubMed1991

The response of retroperitoneal fibrosis to tamoxifen.

Although retroperitoneal fibrosis is uncommon and histologically benign, it is a progressive and potentially fatal tumor. As the fibroblasts proliferate, they encase and may obstruct important retroperitoneal structures. Medical therapy in the past has been ineffectual, and since the tumor usually cannot be resected, surgery consists of lysis or bypass of the involved structures. Tamoxifen is effective in the treatment of desmoid tumors, and we report its use in two patients with retroperitoneal fibrosis with excellent results. The simplicity and safety of this treatment make tamoxifen an attractive choice of therapy.

Female↗
PubMed1988

Efficacy of peroperative liver function tests and ultrasound in detecting hepatic metastasis in carcinoma of the breast.

Two hundred and twenty patients with clinical stage I, II, or III carcinoma of the breast who presented for mastectomy were prospectively evaluated for hepatic metastases with abdominal sonography and routinely available liver enzymes (LE). Both abdominal ultrasound (US) and LE were assessed. There were two false-positive sonogram, both with normal enzymes, in patients with Stage I and II. There was one positive sonogram at presentation in a patient with Stage III, confirmed by needle biopsy, with a lactate dehydrogenase (LDH) elevation. The metastatic yield was low with ultrasound, but other findings were revealed. LE were not useful in the preoperative diagnosis of hepatic metastases, demonstrating a low specificity. Thirty-three patients demonstrated abnormalities of Le. Twenty-seven of 33 had elevation of a single enzyme, LDH being the most common. Three patients had an elevation of four enzymes preoperatively. Hepatic metastases were not diagnosed in these three patients preoperatively on ultrasound or biopsy. The patients were observed with physical examination (PE) and LE for a mean of 26 months. During the follow-up study, 0.9 per cent of the patients with Stage I, 3.4 per cent with Stage II and 12.5 per cent with Stage III had hepatic metastases develop. In patients with these metastases, involvement of the liver was suggested by elevated LE In 66 per cent, on PE in 42 per cent and by history in 28 per cent. LE were the first indication of liver involvement in two patients. We are in agreement with previous authors for abandonment of hepatic imaging in the preoperative assessment because of the low yield for metastases. Forty-eight thousand dollars would have have been spent on this cohort ot diagnose one instance of hepatic metastasis preoperatively. US may be efficacious in the subgroup of patients with grossly elevated LE or a PE suggestive of hepatic involvement. Those patients who demonstrate metastases by us should have histologic confirmation if treatment would thereby be altered.

Adult↗