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Biomedical subjects

J E Carter

Publications and source records attributed to J E Carter.

At least 37 records · Page 2Linked to original sources
PubMed1996

Respiratory rhythm generation in a precocial rodent in vitro preparation.

In vitro preparations for studying the neural control of respiration consisting of brainstem and spinal cord regions isolated from the newborn (PO-P1) precocial rodent, Acomys cahirinus (spiny mouse) are described. Spiny mice have a longer gestation period (39 days) than laboratory rats (22 days) and mice (20 days) and thus are born in a considerably more mature state. We sought to determine if in vitro preparations isolated from spiny mice would spontaneously generate a respiratory motor pattern and thus offer a more mature in vitro model than previously established altricial rodent models. Brain stem-spinal cords isolated from newborn spiny mice, unlike comparable Sprague-Dawley preparations, did not generate a sustained respiratory rhythm. However, spiny mice medullary slice preparations consisting of respiratory rhythm centres generated a stable spontaneous respiratory rhythm. Moreover, spiny mice and Sprague-Dawley medullary preparations responded in a similar fashion to excitatory amino acid, glycine, TRH and, mu-opioid receptor agonists and antagonists. Thus, considering the extended period of fetal development and the maturity of the spiny mouse at birth, medullary slice preparations isolated from this precocial rodent will compliment altricial models for the study of developmental and general neuronal mechanisms underlying respiratory control.

Animals↗
PubMed1996

Aggregation of neurofilaments in NF-L transfected neuronal cells: regeneration of the filamentous network by a protein kinase C inhibitor.

Cytoplasmic inclusion bodies that are accumulations of neurofilaments are the pathological hallmark of many neurodegenerative diseases and have been produced in transgenic mice by overexpression of mouse (NF-L and NF-M; light and medium chains, respectively) and human (NF-M and NF-H; medium and heavy chains, respectively) neurofilament subunits. This report describes a neuronal culture model in which human NF-L was overexpressed to produce cytoplasmic accumulations of neurofilaments within cell bodies concomitant with the collapse of the endogenous neurofilament network. Electron microscopy showed that, within accumulations, neurofilaments retained a filamentous structure. The culture model thus provides a novel system in which the effect on neurofilament accumulations of manipulating protein phosphorylation can be studied. Treatment of cells containing neurofilament accumulations with bisindolylmaleimide, a specific protein kinase C inhibitor, resulted in regeneration of the filamentous network; this effect was not due to a change in the level of transfected NF-L expression. These findings lend support to the suggestion that an impairment in the regulation of protein phosphorylation may lead to the accumulation of neurofilaments seen in neurodegenerative disease.

Actin Cytoskeleton↗
PubMed1996

Thyrotropin-releasing hormone stimulates perinatal rat respiration in vitro.

In the present study, we test whether thyrotropin-releasing hormone (TRH) stimulates respiratory frequency in perinatal rats by acting at regions of the medulla responsible for respiratory rhythmogenesis, the pre-Bötzinger complex. We also test whether TRH stimulates respiration in the fetal rat at a time shortly after the inception of respiratory rhythmogenesis [embryonic days (E) 17-18]. Two in vitro experimental models were utilized: the isolated brain stem-spinal cord preparation from fetal (E17-E18) and neonatal [postnatal days (P) 0-2] rats and the medullary slice preparation isolated from neonatal rats (P1-P2). Bath application of TRH caused a dose-dependent, reversible increase (maximum increase approximately 60%) in the frequency of respiratory rhythmic neural discharge generated by brain stem-spinal cord [half-maximal effective concentration (EC50) approximately 9 nM] and medullary slice (EC50 approximately 2.5 nM) neonatal rat preparations. Pressure injection of TRH unilaterally into the region of the pre-Bötzinger complex of the neonatal medullary slice caused an approximately 28% increase in the frequency of respiratory discharge. Application of TRH to the medium bathing fetal rat brain stem-spinal cord preparations caused an approximately threefold increase in respiratory discharge frequency. We conclude that TRH stimulates respiratory discharge frequency from the time near inception of respiratory motor discharge and acts directly at the pre-Bötzinger complex.

Animals↗
PubMed1996

Childhood IgM nephropathy: comparison with minimal change disease.

The distinctiveness of IgM nephropathy (IgMN) as a clinicopathologic entity is controversial. Twenty-seven children (16 males, 11 females) with IgMN as defined immunohistochemically by diffuse mesangial staining of glomeruli for IgM were compared to a group of 63 children (40 males, 23 females) with minimal change disease (MCD). While mesangial expansion was significantly greater in IgMN than in MCD (p = 0.0014), there were no significant differences between the two groups with respect to the other biopsy factors. IgMN showed a significantly higher incidence of hypertension at presentation. More than 90% of patients in both groups presented with the nephrotic syndrome which in most initially responded to prednisone. Frequently relapsing/steroid-dependent nephrotic syndrome was the most common indication for biopsy in both groups. Approximately 60% of patients from both groups received cytotoxic therapy. Eight percent of IgMN and 7% of MCD patients failed to respond to therapy. Relapse rates and mean dose of prednisone at relapse were very similar in both groups prior to biopsy. Relapse rates diminished significantly after treatment in the postbiopsy interval, but mean dose of prednisone at relapse did not change appreciably over time. None of the patients developed renal failure or hypertension in the follow-up period. At last visit 23% of IgMN and 27% of MCD had proteinuria. The results indicate that IgMN and MCD are indistinguishable clinically in children who are biopsied for the nephrotic syndrome.

Biopsy↗
PubMed1996

Laparoscopic Burch procedure for stress urinary incontinence: the Carter modification.

Bladder neck suspension is now possible under laparoscopic control. The advantages of laparoscopy now apply to laparoscopic colposuspension. The technique described in this paper simplifies the laparoscopic Burch procedure by utilizing the harmonic scalpel for dissection of space of Retzius in a sharp and blunt fashion, providing for a bloodless dissection of the space, suturing of the perivaginal tissue avoiding penetration of the vaginal mucosa, placing the Stamey needle through a small skin incision, allowing for a variation in the shape of the pelvic bone so that the dissection of Cooper's ligament is performed in a very atraumatic fashion, extracorporeal knotting of the suture for ease of fixation of the perivaginal fascia to the Cooper's ligament and stapling of the peritoneal surface for reclosure of the space. With the adoption of this technique, the procedure of laparoscopic bladder suspension can be performed in most cases in approximately 1 hour of surgical time. The results are very encouraging, and the procedure as described in fact does not differ from the classical Burch procedure in any significant detail. Therefore, the long-term results are expected to be similar to those obtained by the standard Burch approach. No failures have thus far occurred in 50 patients over two years follow up. One patient did require urinary drainage through the suprapubic catheter for a period of one week prior to ability to avoid spontaneously.

Humans↗
PubMed1996

Laparoscopic presacral neurectomy utilizing contact-tip Nd: YAG laser.

The performance of the presacral neurectomy with a standard laparoscopic approach utilizing a Contact-tip Nd: YAG Laser with the GRP6 sapphire scalpel tip is feasible, effective, and safe. Patients suffering from severe disabling dysmenorrhea have had complete relief of their symptoms with up to an eighteen-month follow up. The resection of the presacral nerve plexus is associated with significant relief of symptoms. The pain impulses from the uterus which travel through the inferior hypogastric plexus into the intermediate hypogastric plexus and the superior hypogastric plexus can be interrupted by the performance of this procedure in a laparoscopic manner. The intermediate hypogastric plexus which is composed of two or three trunks lying on the vertebral body of L5 is the most appropriate place for the resection. The presacral neurectomy is not appropriate treatment for relief of lateral or back pain. Patients with midline pain will experience significant relief by the use of this procedure. In conclusion, the performance of the presacral neurectomy utilizing the Contact-tip Nd: YAG Laser with GRP6 sapphire tip combined with other conservative surgery for resection of endometriosis does offer relief of dysmenorrhea and other pelvic pain and is an alternative for women wishing further childbearing and those who do not wish a hysterectomy. Twenty women in whom this procedure has been performed have reported a decrease in pain level from 9.4 (scale of 0 = no pain to 10 = disabling pain) to 2.0 with follow up to 18 months. There have been no complications with this procedure.

Dysmenorrhea↗
PubMed1995

Opioid depression of respiration in neonatal rats.

1. The effects of opioid receptor agonists and antagonists on the breathing pattern of neonatal rats were studied. Three experimental approaches were taken. In the first approach, the effects of opioid agonists and antagonists on the spontaneous respiratory neural activity generated by brainstem-spinal cords isolated from neonatal rats aged 0-4 days postnatal (P0-4) maintained in vitro were studied. Secondly, similar studies were performed utilizing medullary slice preparations consisting of respiratory rhythm-generating regions (pre-Bötzinger complex). Thirdly, whole-body plethysmographic recordings were obtained from unanaesthetized neonatal (P0-18) rats before and after I.P. administration of opioid-receptor agonists and antagonists. 2. The mu-receptor agonists morphiceptin and DAGO (Tyr-D-Ala-Gly-[NMePhe]-Gly-ol), when added either to the solutions bathing the brainstems of neonatal rat brainstem-spinal cord preparations or bathing the medullary slice preparations, resulted in a naloxone-reversible, dose-dependent decrease in the frequency of respiratory rhythmic discharge. 3. The respiratory burst frequency and amplitude in vitro were unaffected by the addition of the delta-opioid receptor agonist DPDPE ([D-pen2,5]-enkephalin) and the kappa-opioid receptor agonist U50488 (trans-[+]-3,4-dichloro-N-methyl-N-(2-[1- pyrrolidinyl]cyclohexyl) benzene-acetamide) or the opioid receptor antagonist naloxone. 4. Intraperitoneal administration of the mu-opioid receptor agonist fentanyl resulted in a naloxone-reversible, dose-dependent decrease in the frequency and amplitude of breathing of unanaesthetized neonatal rats (P0-P10). I.P. administration of the delta-opioid receptor agonist DPDPE did not affect breathing of neonatal rats until the second week postnatally. 5. We conclude that opioids suppress the frequency of neonatal rat respiration by acting via mu-opioid receptors located within regions of the ventral medulla containing respiratory rhythm-generating centres (the pre-Bötzinger complex). delta-Opioid receptor activation does not affect breathing in neonatal rats until approximately the second week postnatally.

Analgesics↗
PubMed1995

Laparoscopic treatment of chronic pelvic pain in 100 adult women.

STUDY OBJECTIVE: To evaluate the effectiveness of laparoscopic surgical treatment for women with chronic pelvic pain. DESIGN: Prospective evaluation of women treated consecutively between January 1, 1989, and December 31, 1992. SETTING: A private practice. PATIENTS: One hundred women with chronic pelvic pain. INTERVENTIONS: Laparoscopic treatment was performed in all patients. Pain level was rated on a scale of 1 to 10 (1 = no pain, 10 = severe, disabling pain). Patients recorded their pain levels before and 1 month, 3 months, and 6 months after surgery, as well as at intervals of 1, 2, and 3 years after surgery. MEASUREMENTS AND MAIN RESULTS: Preoperatively, the average pain level reported by the patients was 8.2. At 1 month after laparoscopic surgical therapy, it had dropped to 3.6, at 6 months to 1.9, and at 3 years to 2.2. Twenty patients reported pain levels of 5 or greater at the 6-month interval. Six of them proceeded to hysterectomy, and four of these six were found to have adenomyosis. Eleven of the 100 who had pain levels greater than 5 after initial procedure had no further therapy, and 3 underwent repeat laparoscopy. CONCLUSION: Extensive laparoscopic surgery to restore normal pelvic anatomy and remove all diseased tissue, including treatment of all endometriosis, resection of ovarian cysts, resection of adhesions, removal of the appendix, and treatment of hernias when indicated, together with laparoscopic uterosacral nerve vaporization or presacral neurectomy, results in significant improvement in reported pain levels.

Adolescent↗
PubMed1995

Sulfide-induced perturbations of the neuronal mechanisms controlling breathing in rats.

The effects of sulfide on neonatal rat respiration were studied. Two in vitro experimental models were utilized: the isolated brain stem-spinal cord preparation and the medullary slice preparation containing respiratory rhythm-generating regions from neonatal rats. Plethysmographic measurements of the effects of sulfide on the breathing patterns of unanesthetized neonatal rats were also made to compare the sensitivities of neonatal and adult rats to sulfide toxicity. In vitro, sulfide acted at sites within the ventrolateral medulla to depress the frequency of respiratory rhythmic discharge by approximately 50-60%. However, the neuronal network underlying respiratory rhythmogenesis continued to function in the presence of concentrations of sulfide far beyond those deemed to be lethal in vivo. Intraperitoneal administration of sulfide caused a dose-dependent decrease in the frequency and amplitude of breathing of neonatal rats of all ages (0-19 days postnatal), although the sensitivity to sulfide increased with age. We hypothesize that the rapid suppression of breathing caused by sulfide is due to changes in neuronal excitability within respiratory rhythm-generating centers rather than, as previously hypothesized, to perturbations of cellular oxidative metabolism.

Aging↗
PubMed1995

Effects of cyanide on the neural mechanisms controlling breathing in the neonatal rat in vitro.

The effects of hydrogen cyanide (HCN) on the neural mechanisms controlling breathing were studied. Two in vitro experimental models were utilized; the brain stem-spinal cord and the medullary slice preparations isolated from neonatal rats. Cyanide, at concentrations deemed lethal in vivo (50 microM), caused a modest (< 15%) depression of the frequency and amplitude of inspiratory rhythmic discharge when added to the bathing media. Moreover, the neuronal network underlying respiratory rhythmogenesis continued to function for hours in the presence of very high concentrations of cyanide (600 microM). We hypothesize that the rapid suppression of breathing caused by cyanide in vivo is due to changes in neuronal excitability in respiratory modulating populations in the CNS rather than due to perturbations of cellular oxidative metabolism or neurons within respiratory rhythm generating centres.

Animals↗
PubMed1994

One-and-a-half syndrome, type II.

OBJECTIVE: To describe a second type of the one-and-a-half syndrome in which adduction rather than abduction of one eye is the preserved horizontal movement. DESIGN AND PATIENT SETTING: A patient experiencing mucormycosis of the cavernous sinus suffered a sixth-nerve palsy and simultaneous carotid artery occlusion with infarction and a contralateral horizontal gaze palsy. RESULTS: The patient experienced an eye movement syndrome with complete paralysis of horizontal eye movement in the ipsilateral eye and paralysis of horizontal eye movement in one direction, in this case abduction due to the gaze palsy, in the contralateral eye. Adduction of the contralateral eye was the only remaining horizontal eye movement. CONCLUSION: A lesion in the cavernous sinus producing occlusion of the internal carotid artery and a sixth-nerve palsy may produce a second type of one-and-a-half syndrome. Adduction rather than abduction of one eye is the preserved horizontal eye movement. This combination of eye movement deficits is unlikely to be produced by a lesion in any other location. Mucormycosis, with its propensity to produce vascular occlusion, is a likely, although not specific, cause.

Abducens Nerve↗
PubMed1994

Laparoscopic-assisted vaginal hysterectomy: a case control comparative study with total abdominal hysterectomy.

We compared laparoscopic-assisted vaginal hysterectomy (LAVH) with total abdominal hysterectomy (TAH) in a case control study that evaluated length of operation, blood loss, length of hospital stay, drug requirements for pain, and postoperative pain and activity levels. Of 81 women who underwent nonradical hysterectomy for a primary diagnosis of pelvic pain between June 1 and December 31, 1992, 19 who underwent each procedure were chosen for inclusion in the study. Patients were matched in a case control manner with age, weight, diagnosis, and uterine weight. All 38 hysterectomies were completed without incident. When indicated, unilateral or bilateral oophorectomies were performed. The average surgery time for LAVH was 144 minutes and for TAH 98 minutes, a significant difference (p <0. 005). There were no significant differences between estimated blood loss and change in hemoglobin from preoperative levels to postoperative day 1 levels between the groups. Women having TAH reported significantly more pain after their release from the hospital. There was no significant difference in pain during hospitalization apparently because patients who had TAH self-medicated to maintain acceptable levels. That group in fact used an average of 436 mg meperidine during their hospital stay, significantly more than the 197 mg used by the LAVH group (p <0.005). The length of stay was 2.125 days for LAVH and 3.542 days for TAH (p <0.001). On a scale of 1 to 10 (10 being complete normal activity) the activity level of women undergoing LAVH was 9.2 by day 14 compared with 6.4 for those having TAH (p <0.005). By the sixth postoperative week the latter group reported an activity level of only 8.5, indicating that the ability to function is much more severely limited after TAH than LAVH.

Adult↗
PubMed1994

Combined hysteroscopic and laparoscopic findings in patients with chronic pelvic pain.

STUDY OBJECTIVE: To document the abnormal findings at hysteroscopy and laparoscopy in patients with chromic pelvic pain. DESIGN: Prospective evaluation at surgery of women treated consecutively between January 1, 1991, and December 30, 1992. SETTING: A private practice. PATIENTS: One hundred forty-one women with pelvic pain (average age 35 yrs). INTERVENTIONS: Laparoscopy was performed in all patients, and hysteroscopy in all but one, who had had a hysterectomy. Endometrial and endocervical biopsies were performed. MEASUREMENTS AND MAIN RESULTS: In 42 (30%) of 140 patients with a primary diagnosis of chronic pelvic pain hysteroscopic evaluation with endometrial and endocervical biopsies revealed an abnormality. Findings at hysteroscopy included leiomyomas in 25 patients (18%), intrauterine polyps in 9 (6.4%), and cervical stenosis in 4 (2.9%). Three women (2.1%) had intrauterine scarring and one (0.7%) had a bicornuate uterus. Endometrial biopsies showed adenomatous hyperplasia with atypia, and cystic hyperplasia in one patient each. Endocervical biopsies revealed cervical dysplasia in four women (2. 89%). An abnormal finding was documented on laparoscopic examination in all 141 patients. These included endometriosis in 113 patients (80%), adhesions in 67 (48%), leiomyomas in 59 (42%), and enlarged globular uterus in 34 (24%). In addition, appendiceal abnormalities were present in three women (2.1%) and hernia in two (1.4%). CONCLUSIONS: Hysteroscopic abnormalities were found in 30% and laparoscopic abnormalities in 100% of patients who had a primary diagnosis of chronic pelvic pain.

Adolescent↗
PubMed1994

Physique and motor performance characteristics of US national rugby players.

Anthropometric and performance data were collected on 65 US rugby players (mean age = 26.3 years) to make comparison on these characteristics by player position and performance level. Anthropometry included stature, body mass, nine skinfolds, two girths and two bone breadths. Skinfold patterns, estimated percent fat and Heath-Carter somatotypes were calculated from anthropometry. Motor performance measures included standing vertical jump, 40 yard dash, 110 yard dash, shuttle run, repeated jump in place, push-up, sit-up and squat thrust. Descriptive statistics were used for the total sample as well as selected sub-groups. Discriminant function analyses were employed to determine which combination of variables best discriminated between position and level of performance for the anthropometric and performance data. The results indicated that forwards were taller, heavier and had more subcutaneous adiposity than backs. Additionally, forwards and backs differed in somatotypes, with forwards being more endo-mesomorphic than backs and with a greater scatter about their mean. The anthropometric variables that best discriminated between backs and forwards were body mass, femur breadth and arm girth, with 88% correctly classified using these variables. The motor performance variables that best discriminated between backs and forwards were repeated jump in place, push-up and standing vertical jump, with 76% correct classification using these variables. Classification into three playing levels was unsatisfactory using either anthropometric or motor performance variables. These data can be used to assess present status and change in players, or potential national players, by position to locate strengths and weaknesses.

Abdominal Muscles↗
PubMed1994

A new technique of fascial closure for laparoscopic incisions.

The objective was to develop a technique and instrumentation for closure of 10-mm and larger laparoscopic incisions with a single instrument under direct laparoscopic vision, ensuring complete fascial and peritoneal closure. The Carter-Thomason Needle-Point Suture Passer functions as both a needle and a grasper, allowing for performance of laparoscopic directed fascial and peritoneal closure. It uses a 2.7-mm diameter grasping tool with a single-action jaw. The device introduces the suture through the muscle, fascia, and peritoneal layers under direct laparoscopic vision, drops the suture, picks it up at the opposite side of the opening, and is withdrawn grasping the suture. The surgeon completes the mass closure of the layers by tying the suture below the skin. Pneumoperitoneum is maintained. The closed peritoneal layer is viewed through the laparoscope, and palpation of the closure ensures that the fascial layer is completely occluded. The Carter-Thomason Needle-Point Suture Passer has been used as a single instrument for closure of 10-mm and larger incision sites in over 200 advanced laparoscopic procedures since March 1993. No incisional hernias or complications of the incisional site have occurred. This instrument and the technique have been used for ligation to control hemorrhage from a lacerated inferior epigastric vessel, with successful ligation obtained in less than 5 min. It also was used to pass suture to allow ligation of the infundibulopelvic ligament. This device provides complete and secure closure of operative incisions of 10 mm or larger, thereby reducing the risk of herniation during the postoperative recovery period.

Appendectomy↗
PubMed1994

Sustained reversal of right-to-left atrial septal defect flow after pulmonic valvuloplasty in an adult.

A 60-year-old man with Noonan's syndrome presented with generalized weakness, dyspnoea, and paresthesias. He was known to have pulmonic stenosis and atrial septal defect with right-to-left shunting and had refused therapy for many years. On presentation there was cyanosis and the haematocrit was 63%. After phlebotomy he was treated with balloon valvuloplasty. There was marked reduction in the transpulmonic gradient and oximetric evidence for reversal of his right-to-left atrial septal defect flow. After 18 months follow-up he remained system free and had no rise in haematocrit, consistent with no return of right-to-left shunting.

Catheterization↗