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Biomedical subjects

L Gordon

Publications and source records attributed to L Gordon.

At least 37 records · Page 2Linked to original sources
PubMed1995

Greater secretion of growth hormone in black than in white men: possible factor in greater bone mineral density--a clinical research center study.

To determine why blacks have a higher bone mineral density (BMD) and lower incidence of osteoporosis and fractures than whites, we investigated whether the secretion of GH is higher in black than in white men. Measurements of GH were obtained at 20-min intervals over 24 h and analyzed by deconvolution. BMD was determined by dual energy x-ray absorptiometry in 16 normal black and 17 normal white men, aged 20-40 yr. The 24-h integrated GH concentration 942 +/- 174 vs. 602 +/- 104 micrograms/L; P = 0.0495) and GH secretory burst amplitude (0.499 +/- 0.163 vs. 0.169 +/- 0.027 micrograms/L.min; P = 0.0482) were higher in black than in white men. GH burst frequency, half-duration, mass, and half-life were not different in the 2 groups. The serum 17 beta-estradiol level (162 +/- 12 vs. 108 +/- 11 pmol/L; P = 0.0011) was higher, and the serum insulin-like growth factor-binding protein 3 level (2.2 +/- 0.1 vs. 2.8 +/- 0.1 microgram/mL; P = 0.0001) was lower in black than in white men. BMD values for total body (1.22 +/- 0.02 vs. 1.14 +/- 0.02 g/cm2; P = 0.0041), forearm (0.69 +/- 0.01 vs. 0.66 +/- 0.01 g/cm2; P = 0.0211), trochanter (0.91 +/- 0.03 vs. 0.77 +/- 0.03 g/cm2; P = 0.0003), and femoral neck (1.08 +/- 0.03 vs. 0.93 +/- 0.03 g/cm2; P = 0.0007) were higher in black than in white men. Thus, serum 17 beta-estradiol level, GH secretion, and BMD values for the total body, forearm, trochanter, and femoral neck are greater in black than in white men. As estrogen is known to increase GH secretion and GH to increase bone mass, increases in circulating 17 beta-estradiol may contribute to the higher GH secretion and bone mass in black men.

Absorptiometry, Photon↗
PubMed1995

Position of the wrist associated with the lowest carpal-tunnel pressure: implications for splint design.

Increased carpal-tunnel pressure has been implicated in the pathophysiology of carpal tunnel syndrome, but it is not known whether splints that immobilize the wrist in a functional position of extension minimize carpal tunnel pressure. To determine the position of the wrist that results in the lowest carpal-tunnel pressure, twenty control subjects and four patients who had carpal tunnel syndrome were evaluated with use of a new, dynamic method that continuously measures carpal tunnel pressure throughout the range of motion of the wrist. The pressure was measured by means of a pressure transducer connected to a flexible catheter that had been inserted into the carpal canal. The position of the wrist was measured simultaneously with use of a two-axis electrogoniometer. Aided by a computer monitor that displayed a moving line of real-time carpal-tunnel pressure, each subject was instructed to move the wrist throughout the range of motion and to adjust it to the position that corresponded to the lowest carpal-tunnel pressure. For the control subjects, the lowest carpal-tunnel pressure averaged 8 +/- 4 millimeters of mercury (1.07 +/- 0.53 kilopascals), and the average position of the wrist associated with the lowest pressure was 2 +/- 9 degrees of extension and 2 +/- 6 degrees of ulnar deviation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Gene organization of the pregnancy-specific glycoprotein region on human chromosome 19: assembly and analysis of a 700-kb cosmid contig spanning the region.

The pregnancy-specific glycoprotein (PSG) gene family consists of 11 closely related genes that form a subgroup of the carcinoembryonic antigen (CEA) gene family on 19q13.2. Using a high-resolution restriction fragment fingerprinting technique, we have assembled 256 cosmids from the PSG region into a single 700-kb contig. Fluorescence in situ hybridization to sperm pronuclei and cosmid walking experiments indicated that this PSG contig was directly telomeric of CGM8 at the telomeric end of the CEA subgroup gene cluster. Detailed restriction mapping and hybridization with gene-specific probes indicated that the order of the 11 Previously identified PSG genes is cen-PSG3-PSG8-PSG12-PSG1-PSG6-PSG7-+ ++PSG13-PSG2-PSG5-PSG4-PSG11-tel. The CEA subgroup gene CGM11 is located at the telomeric end of the PSG gene cluster. The PSG genes are all oriented in tandem with the 5'-3' direction of transcription from telomere to centromere. The detailed map also led to the identification of seven new CEA family genes in this region. One of these (CGM12), located between CGM8 and PSG3, is a member of the CEA subgroup. The remaining six (CGM13 through CGM18) are interspersed among the PSG genes and appear to form a third distinct subgroup within the CEA gene family.

Animals↗
PubMed1994

Use of Norplant implants in a New York City clinic population.

Two-hundred-eight women attending family planning clinics in New York City who received the Norplant contraceptive system during the first sixteen months of Norplant implants insertions were evaluated. Within this clinic population, Norplant implants were a popular contraceptive choice and were removed from 64 of the 208 recipients. Reasons for removal included bleeding, weight gain, and headache, and were consistent with those found in the clinical trials. Prior satisfaction with oral contraceptives did not predict success or failure with Norplant implants. The rate of follow-up visits to the family planning clinics was low. However, evidence exists that these women did not lose contact with the medical center and continued to receive health care.

Adult↗
PubMed1994

The effect of wearing a flexible wrist splint on carpal tunnel pressure during repetitive hand activity.

We investigated how repetitive hand activity normally affects carpal tunnel pressure and whether a flexible wrist splint can influence this effect. Nineteen healthy subjects were evaluated under four test conditions: at rest with and without a wrist splint (baseline) and while performing a repetitive task with and without a wrist splint. The task involved loading and unloading 1 lb. cans from a box at a rate of 20 cans per minute for period of 5 minutes. Carpal tunnel pressure and wrist angles were continuously monitored by means of a fluid-filled catheter inserted into the carpal canal and a two-channel electrogoniometer mounted on the dorsum of the hand and forearm. Without the splint, carpal tunnel pressure rose from a median baseline level of 8 +/- 6 mmHg to 18 +/- 13 mmHg during activity. With the splint, carpal tunnel pressure rose from a baseline of 13 +/- 5 mmHg to 21 +/- 12 mmHg during activity. Median carpal tunnel pressure during activity with the splint was no different from that without the splint. Our data indicate that the median nerve is subjected to increased pressure within the carpal tunnel during repetitive hand activity. Wearing a flexible wrist splint during activity limits the range of wrist motion but has no significant effect on carpal tunnel pressure.

Adult↗
PubMed1994

A segment of the MHC class II beta chain plays a critical role in targeting class II molecules to the endocytic pathway.

The ability of MHC class II molecules to sort into the endocytic pathway has generally been attributed to the invariant chain glycoprotein. In this paper, we present evidence suggesting that lumenal sequences in the MHC class II molecule itself control the post-Golgi entry of class II into endosomes. Single amino acid changes have been introduced into a highly conserved region of the class II beta chain (amino acids 80-83). Mutant class II beta chain genes and wild-type alpha chain genes have been transfected into cells that lack both class II and invariant chain expression. Immunofluorescent staining of transfected cells indicates that single amino acid changes in this region of beta can positively or negatively modulate expression of class II in endocytic vesicles independently of invariant chain. Mutation at residue 80 leads to prominent localization in vesicular structures typical of late endocytic compartments, while a change at position 82 leads to arrest in the Golgi. These data argue in favor of the possibility that MHC class II molecules bear a sorting signal that allows access to MHC class II molecules into the endocytic pathway of antigen presenting cells.

Animals↗
PubMed1994

Scintigraphic diagnosis of peritoneo-pleural communication in the absence of ascites.

Pleural effusion in the presence of cirrhosis and ascites is well recognized. Peritoneal fluid is thought to enter the pleural cavity either because of overloaded lymphatics or a structural defect between the peritoneal and chest cavities. Pleural effusion rarely occurs in the absence of demonstrable ascites. This report describes the scintigraphic diagnosis of peritoneo-pleural communication in a patient with cryptogenic cirrhosis and pleural effusion without ascites.

Ascites↗
PubMed1994

Transport proteins and acute phase reactant proteins in children with sickle cell anemia.

Transport proteins, acute-phase reactant proteins (APRP), hematology, and anthropometry were studied in 34 sickle cell disease (SCD) children (20 boys, 14 girls) and 27 controls without growth deficits (13 boys, 14 girls) [corrected]. The age range was 1/2 to 16 1/2 years. Weight deficits (< 80%) by Waterlow's classification were observed in 41% of SCD boys and 25% of SCD girls, and height deficits (< 90%) were observed in 25% SCD boys and 25% girls. Mean white blood cell counts were significantly higher (P < .001) and hematocrit and hemoglobin (Hb) lower (P < .005) in SCD children than in controls. Although both groups had similar mean levels of albumin, transferrin, and APRP, SCD children had significantly lower mean levels of retinol-binding protein (RBP) (P < .001) and retinol-prealbumin (P < .001). Retinol-binding protein levels were abnormal in 18 (53%) SCD children and in only 23% controls (chi 2 = 14.06; P < 0.005); transferrin levels were abnormal in 20% of SCD children and in none of the controls. Children with SC and SF Hb phenotype had normal mean levels of RBP, whereas those with S beta thal and SS phenotype had levels below normal. Growth-retarded children by weight and height had reduced mean levels of RBP and prealbumin compared with growth-normal SCD children. The implication of primary protein-energy malnutrition on growth retardation in SCD children is under study.

Acute-Phase Proteins↗
PubMed1993

Expression of the human neuropeptide tyrosine Y1 receptor.

Neuropeptide tyrosine (NPY) is the predominant peptide in the innervation of many human tissues and is considered to play a role in the regulation of blood flow, gastrointestinal secretion and motility, and renal function. Three NPY receptors have been identified (Y1, Y2, and Y3) and the cDNAs encoding the human Y1 and bovine Y3 receptors have recently been cloned. We have demonstrated the expression of the Y1 receptor subtype in several fetal and adult human tissues, including the colon, kidney, adrenal gland, heart, and placenta. A single transcript was identified (approximately 2.2 kb) and localized in tissue sections by in situ hybridization. In the colon the receptor is expressed in the mucosa and basal glands, as well as the myenteric and submucous plexuses. Y1 receptor mRNA was detected in renal collecting ducts, loop of Henle, and juxtaglomerular apparatus and in the syncytiotrophoblast layer of placental villi. Fetal aorta and adult intramyocardial, colonic, and renal blood vessels also exhibited receptor expression, localized to the intima as well as the media. The distribution of Y1 receptor expression correlates with that of NPY-immunoreactive nerves and the apparent actions of NPY in the intestine, kidney, and heart. Although the placenta is devoid of nerves, an NPY-like transcript was detected in the villous trophoblast layer. The results indicate a tissue-specific regulation of NPY Y1 receptor expression.

Adult↗
PubMed1993

Organization of the multiple polymorphic sites of the D19S11 locus within a 650-kb cosmid contig.

The D19S11 locus has been previously described as consisting of a complex set of six nonallelic polymorphic sites detected with a combination of four restriction enzymes and three probes that were subcloned from a single cosmid. These probes also hybridized to additional nonvariant fragments on Southern blots of human genomic DNA. In the course of establishing a contig map of human chromosome 19, a set of cosmids that were positive for at least one of the probes defining this locus was identified. These cosmids, along with additional cosmids, were assembled using a combination of strategies, including fluorescence in situ hybridization studies using G1 interphase nuclei and sperm pronuclei as chromatin targets, into a single overlapping set of cosmids that spans approximately 650 kb. Cosmids that are positive for the MEL gene probe are localized at the centromeric end of the spanning path, with some cosmids being positive for both the MEL gene probe and one of the D19S11 probes. The EcoRI fragments with homology to the various probes have been identified; some cosmids have homology to all three D19S11 probes. The positions for five of the six polymorphic sites were localized within a 40-kb region, with four sites within 15 kb.

Blotting, Southern↗
PubMed1993

Quantitative immunohistochemical assessment of bovine myocardial innervation before and after cryosurgical cardiac denervation.

OBJECTIVE: The aim was to determine the relative distribution and possible origins of peptide containing nerves in the bovine heart before and after functional extrinsic denervation established by cryosurgery. METHODS: A quantitative immunohistochemical technique was used. RESULTS: In the intact heart, myocardial nerve fibres and fascicles displaying immunoreactivity for the general neural marker protein gene product 9.5 had an atrial to ventricular gradient in density. The right atrium was the most densely innervated region and a major proportion of the total myocardial innervation, visualised by protein gene product 9.5 immunoreactive nerves, showed neuropeptide tyrosine (45%) and tyrosine hydroxylase (20%) immunofluorescence staining, while nerves immunoreactive for vasoactive intestinal polypeptide and calcitonin gene related peptide formed relatively minor subpopulations (representing less than 2% and 0.5%, respectively, of the total fluorescent myocardial innervation). Following cryoablation there was a significant reduction in the percentage fluorescent area of protein gene product 9.5 immunoreactive nerves throughout the heart, of greater than 90% of the control values. There were highly significant reductions in the percentage fluorescent area of nerves showing immunoreactivity to neuropeptide tyrosine, tyrosine hydroxylase, and calcitonin gene related peptide, to 1.01, 0.92, and 0.05%, respectively, of the intact myocardial innervation. The distribution of vasoactive intestinal polypeptide immunoreactive nerves was more variable and displayed an equivocal response to cardiac cryoablation. CONCLUSIONS: The majority of nerves showing immunoreactivity to neuropeptide tyrosine, tyrosine hydroxylase, and calcitonin gene related peptide are of extrinsic origin, while vasoactive intestinal polypeptide immunoreactive nerves may have intrinsic as well as extrinsic origins. The distribution and apparent origins of immunohistochemically defined nerves in the bovine heart are similar to those observed in the human heart which suggests that the calf may be an appropriate model for comparative studies.

Animals↗
PubMed1993

The diagnosis of brain death with Tc-99m HMPAO.

Evaluation of blood flow to the brain using various radiopharmaceuticals can be used to confirm brain death. Agents available for this purpose include Tc-99m HMPAO, Tc-99m pertechnetate, Tc-99m glucoheptonate, and Tc-99m DTPA. The authors evaluated the use of Tc-99m HMPAO in 17 patients suspected of brain death using flow images and static images at several time intervals: immediately, between 30 and 60 minutes, and at 2 hours. These studies were compared to several studies performed with Tc-99m glucoheptonate and Tc-99m DTPA. The results of the Tc-99m HMPAO brain death studies correlated well with the patients' clinical conditions. Static images 1 to 2 hours after the injection of 5 to 30 mCi of Tc-99m HMPAO were satisfactory for an accurate interpretation; however, an immediate answer could as easily be supplied using flow images alone. Tc-99m HMPAO was found to be more easily interpreted and less dependent on imaging technique than Tc-99m glucoheptonate and Tc-99m DTPA, and it is the agent of choice for the evaluation of brain death.

Adolescent↗
PubMed1993

The serratus anterior free-muscle transplant for reconstruction of the injured hand: an analysis of the donor and recipient sites.

The present study evaluated donor-site function in eight patients for whom serratus anterior free-muscle transplantation was performed to treat a traumatic defect of the palm. The lowest two or three slips of the muscle were transferred from the uninjured side and covered with split-thickness skin grafts. After an average follow-up period of 50 months (range 13 to 84 months), function and appearance of the flaps were assessed, and shoulder strength on the donor side was objectively tested in six patients by using an isokinetic computerized robotic dynamometer. No patient noticed any change in upper extremity function following the procedure. Each of the three patients in whom three slips had been taken displayed mild scapular winging, but none complained of any related symptoms. Neither push strength nor abduction strength on the donor side was significantly different compared with that on the recipient side. The transplanted muscle provided excellent contour and durable cover in all eight hands with limited donor-site morbidity. For this reason, the serratus anterior transplant is our flap of choice for the treatment of large palmar defects.

Adult↗