Influence of exercise order in a resistance-training exercise session

The order of resistance exercises within a training session may have a vital impact on the quality of the constituent exercises performed. However, very few studies have documented the specific influence of exercise order. Therefore, the purpose of this study was to examine the effect of exercise order on back squat performance in the context of a whole-body workout. Nine resistance-trained male subjects (age: 24 +/- 4 years, body mass: 81.5 +/- 15.3 kg, resistance-training experience: 7 +/- 4 years) performed the back squat exercise (4 sets at 85% of 1 repetition maximum) on 2 separate occasions in a balanced, crossover design. During one protocol, the squat exercise was performed first (protocol A); during the other protocol, it was performed after a whole-body resistance-exercise session (protocol B). Number of repetitions, average power, and rating of perceived exertion (RPE) were collected during each set of the squat exercise. All subjects performed significantly (p < 0.01) more repetitions during set 1 when they performed protocol A (8.0 +/- 1.9 repetitions) compared with protocol B (5.4 +/- 2.7 repetitions). The average power for each set was higher during protocol B compared with protocol A. There were no significant differences in RPE values between the 2 protocols. In conclusion, performing the barbell back squat first in an exercise session allowed the completion of more total repetitions. However, this study showed that performing the squat exercise after a whole-body workout session may result in greater power output if the squat is preceded by a power exercise (i.e., hang pull). This phenomenon may have been due to postactivation potentiation.     

Skin-sparing mastectomy and immediate autologous tissue reconstruction after whole-breast irradiation

Traditional breast conservation therapy consists of lumpectomy and whole-breast irradiation. Local recurrence after breast conservation is usually managed with salvage mastectomy. Skin-sparing mastectomy and immediate autologous tissue reconstruction is an accepted method of managing primary breast malignancies with exceptional aesthetic results. The purpose of this study was to evaluate this technique in the previously irradiated breast. This study is a retrospective review of all patients undergoing skin-sparing mastectomy and immediate reconstruction with autologous tissue after failed breast conservation therapy between 1995 and 1999. There were 11 patients with a mean age of 45 years (range, 34 to 58 years). Initial lumpectomy was performed for ductal carcinoma in situ in six patients and infiltrating carcinoma (ductal or lobular) in five patients. The interval from lumpectomy to salvage mastectomy ranged from 12 to 169 months (mean, 44 months). Reconstructive techniques included unipedicled transverse rectus abdominis musculocutaneous (TRAM) flap (n = 4), free TRAM flap (n = 4), and latissimus flap with immediate placement of a saline implant (n = 3). Flap survival was 100 percent, and there were no early flap complications. One patient developed partial-thickness mastectomy flap loss (3 x 3 cm), which was managed conservatively. There were no instances of full-thickness mastectomy skin loss. Late complications included capsular contracture (n = 2), fat necrosis (n = 1), and ventral hernia (n = 1). There was one late death from metastatic disease; the remaining patients were without evidence of disease at a mean of 48 months (range, 30 to 75 months). Aesthetic results were judged as excellent (n = 4), good (n = 5), fair (n = 1), and poor (n = 1). These results demonstrate that skin-sparing mastectomy and immediate autologous tissue reconstruction can be safely performed in patients with previous whole-breast irradiation. Clearly, patient selection is paramount with attention to the quality of the irradiated breast skin and the anatomic location of the recurrent disease. In this experience, the best results were seen after TRAM (pedicled or free) flap reconstruction.     

Pulsatile ACTH secretion: variation with time of day and relationship to cortisol

It has long been known that ACTH is secreted in an episodic fashion demonstrating circadian and ultradian rhythms. High intensity venous sampling has recently revealed that in addition to these larger ultradian fluctuations in hormone levels, plasma ACTH in rats demonstrates high frequency, low amplitude oscillations which have been called "micropulses." These micropulses were not detected in previous studies due to sampling intervals of greater than 5 minutes. To investigate the presence of these ACTH micropulses in a primate species, blood samples were drawn from six chair-restrained rhesus monkeys at one-minute intervals for up to 70 minutes and plasma was assayed for immunoreactive ACTH. To assess the variation in ACTH micropulse parameters with time of day and the relationship to cortisol secretion, four of the monkeys were sampled for three 70-minute periods beginning at 0530, 1100, and 1730 hours, and plasma was assayed for immunoreactive ACTH and cortisol. Analysis of the data revealed that ACTH and cortisol are secreted in micropulses in rhesus monkeys with marked individual variation in the pattern of secretion and a concurrence of approximately 75% of ACTH and cortisol micropulses. Difference in pulse amplitude but not frequency appeared to contribute to the circadian variation in mean ACTH levels and a sampling interval of two minutes appeared to be adequate for accurately identifying micropulses of ACTH.     

Efficacy of operative cure in pressure sore patients.

The advent of air flotation-type beds and purified growth factors that may accelerate open wound contraction, coupled with very high recurrence rates and decreasing health resources, suggests that surgical reconstruction of pressure sores may not be indicated in all patients. In an effort to define which patients might benefit from operation, we reviewed the data from 40 consecutive patients with 68 pressure sores operated on under the direction of a single surgeon between 1981 and 1989. Patients were categorized on the basis of the presence or absence of paraplegia and its etiology. Sixty-six operations were performed, 55 muscle or fasciocutaneous flaps and 11 cutaneous flaps. There was a 36 percent operative complication rate, with no operative mortalities. Follow-up ranged from 1 to 71 months, with a mean of 21 months. Despite an 80% healed rate at the time of discharge, 61% of sores and 69% of patients had recurrent ulceration within a mean of 9.3 months. Analysis of these data indicates that surgical reconstruction of pressure sores does not appear to be efficacious in young posttraumatic paraplegics or cerebrally compromised elderly patients. Further review of the data failed to identify those patients likely to remain healed after operative repair of their pressure sores.     

Ultrastructural immunocytochemical co-localization of serotonin and PNMT in adrenal medullary vesicles

Summary Previous immunocytochemical studies at the light microscopic level have demonstrated serotonin immunoreactivity in rat adrenal epinephrine-containing cells. In this study we have used electron microscopic immunocytochemical methods to study the subcellular distribution of serotonin and the enzyme responsible for epinephrine biosynthesis, phenylethanolamine-N-methyltransferase (PNMT). The distribution of the immunostaining was compared in adjacent serial thin sections using a post-embedding method in conjunction with peroxidase-antiperoxidase (PAP) immunocytochemistry. Serotonin immunoreactivity was associated with the limiting membrane as well as with the core of the chromaffin vesicles. In adjacent sections PNMT immunoreactivity was also seen in the serotonin-containing vesicles. However, its intravesicular distribution was different from that of serotonin; PNMT occupied the eccentric zone of the vesicles between the serotonin immunoreactive sites.These results are interpreted to be in support of biochemical studies claiming a serotonin uptake and storage capacity of adrenal chromaffin vesicle fractions as well as those which suggest serotonin is synthesized by chromaffin cells. The relative contribution of uptake and synthesis to the pool of serotonin that is stored in the vesicles is an open question. The co-localization of serotonin and PNMT in the same vesicle is suggestive of a capacity for co-release of serotonin and epinephrine by the adrenal medulla.     

In vitro evidence for a blood-borne renin-releasing factor

The present studies using kidney slices were designed to test whether serotonergic stimulation of renin secretion is mediated via an endocrine signal. Previous in vivo studies have indicated that central serotonergic neurons regulate renin secretion. Administration of the serotonin releaser dl-p-chloroamphetamine-HCl (PCA) to rats causes dose-dependent increases in renin secretion that can be blocked by serotonin depletion with p-chlorophenylalanine (PCPA), injections of 5,7-dihydroxytryptamine into the dorsal raphe nucleus or ablation of the mediobasal hypothalamus. The renin-releasing substance was obtained from nephrectomized male donor rats which were sacrificed 1 hour after receiving an injection of PCA intraperitoneally. Plasma from rats that received saline injections was used as control. The plasma was collected and separated by ultrafiltration into fractions containing solutes with molecular weights between 500-10,000 daltons. The renin-releasing ability of this substance was studied in vitro using rat renal cortical slices. The plasma fraction (M.W. = 500 - 10,000) from rats treated with PCA caused dose-dependent increases in renin release from the kidney slices. Heating of the plasma factor at 100 degrees C for 30 minutes did not reduce the ability of this substance to release renin from the kidney slices. PCA alone (66 X 10(-6)M) did not increase renin release from the kidney slices. These data suggest that stimulation of serotonergic receptors in the brain triggers the release of an endocrine factor that is capable of directly stimulating renin release from the kidneys.