Search PubMed⌕ Search

Biomedical subjects

T J Moore

Publications and source records attributed to T J Moore.

At least 73 records · Page 4Linked to original sources
PubMed1990

Vascular smooth muscle cells from the Milan hypertensive rat exhibit decreased functional angiotensin II receptors.

The present study was designed to study the functional properties of Angiotensin II (Ang II) binding sites in vascular smooth muscle cells in the Milan hypertensive rat (MHS), a model of low renin hypertension. Smooth muscle cells from MHS rats exhibited increased growth in culture in comparison with the Milan normotensive strain (MNS) as determined by population doubling times (24.5 +/- 2 and 34.8 +/- 2 hours, n = 4, respectively). Hormone receptor number, evaluated by binding assays using [125I]Ang II, showed no difference in either receptor number or affinity for both cell types. The functional responsiveness of Ang II receptors was evaluated by measuring the activation of phospholipase C, Na(+)-H+ exchange, and cytosolic Ca2+ levels. Phospholipase C activity was determined as tritium-labeled inositol trisphosphate and bisphosphate release before and after 15-second exposure to 10(-7) M Ang II. Ang II-stimulated phospholipase C activity in MNS (p less than 0.02) but not in MHS cells. Na(+)-H+ exchange was measured as the dimethylamiloride-sensitive 22Na+ influx into acid-loaded vascular smooth muscle cells with and without 10(-7) M Ang II. In MNS cells, Ang II significantly stimulated (p less than 0.001) antiporter activity but not in MHS cells, which showed a uniformly blunted response. MHS cells exhibited higher basal cytosolic Ca2+ levels than MNS cells, but Ca2+ rapidly increased in the presence of Ang II in MNS but not in MHS cells. Direct activation of phospholipase C by GTP-gamma-S in permeabilized cells indicated that both strains exhibited similar coupling levels by guanine-nucleotide binding proteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗
PubMed1990

Knee function after complex femoral fractures treated with interlocking nails.

Twenty-three complex femoral fractures were treated with interlocking nails. After fracture healing, knee function was analyzed, including alignment, quadriceps and hamstring strength, thigh atrophy, and range of motion (ROM). Similar to previous studies in the preinterlocking nail era, knee function was impaired in comparison with the contralateral limb. Seventy-three percent of patients had decreased quadriceps strength, and 60% had decreased hamstring strength. Sixty-five percent had thigh atrophy. The ROM and alignment were satisfactory. Despite the advantages of early ROM with femoral fractures treated with interlocking nails, knee function is often unsatisfactory once fracture union has occurred. Therefore, a formal knee rehabilitation program is recommended to achieve an optimal result.

Adolescent↗
PubMed1990

Effect of whole-body vibration on acoustic measures of speech.

If Automatic Speech Recognition technology is to be applied in the cockpit, it must deal with speech produced under environmental conditions that may alter the acoustic characteristics of the speech to be recognized. The present study examines the acoustic-phonetic detail of selected words produced under vibration, with the talker wearing an oxygen mask. The duration of words and syllables showed small effects that were inconsistent and statistically non-significant. Statistically significant increases were found in fundamental frequency and in the proportion of energy in the higher frequencies (decreased spectral tilt). The vibration conditions examined had no consistent effect on the center frequencies of the vowel formants measured.

Aviation↗
PubMed1989

Reduced angiotensin receptors and pressor responses in hypotensive hemodialysis patients.

A sub-set of patients on chronic hemodialysis develop sustained hypotension (systolic pressure less than 100 mm Hg). To determine whether this hypotension could be due to altered production of, or sensitivity to angiotensin II (AII), we measured plasma renin (PRA), AII, and aldosterone in nine hypotensive and nine normotensive dialysis patients; we also assessed their sensitivity to infused AII and studied AII binding to their platelets as an indicator of AII receptors on vascular smooth muscle. All studies were performed just before dialysis when subjects were relatively volume-expanded. Hypotensives had higher PRA (5.7 +/- 2.4 vs. 2.1 +/- 0.8 ng AI/ml/hr, P less than 0.05). AII (56 +/- 15 vs. 31 +/- 3 pg/ml), and aldosterone (91 +/- 35 vs. 21 +/- 7 ng/dl, P less than 0.05) than did normotensives. During AII infusion at 1, 3, 10, and 30 ng/kg/min for 15 minutes each, hypotensives displayed a significantly blunted pressor effect across the range of AII doses. In parallel with this, hypotensives showed reduced AII receptors on their platelets compared to normotensives (0.8 +/- 0.4 vs. 3.6 +/- 1.0% 125I-AII specifically bound; P less than 0.03). Binding analysis revealed a single affinity state for the AII receptors which was similar in both groups (Kd = 3.2 +/- 1.1 for hypotensives vs. 3.8 +/- 0.7 x 10(-10) M for normotensives). The two groups had similar levels of plasma catecholamines, similar slowing of heart rate during AII infusion and no postural hypotension, indicating intact sympathetic nervous system pathways.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

The role of dietary electrolytes in hypertension.

The possible contribution of dietary electrolyte intake as a cause of or contributor to the development of hypertension has been intensively investigated for over 50 years. Evidence from various sources suggests a role for sodium-salt, chloride, calcium, and magnesium. In this article, we will review the evidence supporting a role for each of these electrolytes in human hypertension.

Calcium↗
PubMed1989

Severe trauma to the lower extremity: long-term sequelae.

Limb salvage after major traumatic injury to the lower extremity has become commonplace in modern trauma centers. Despite initial successful limb salvage, however, long-term complications often occur. We present 121 patients who were treated for complications after major injuries to the lower limb at Rancho Los Amigos Medical Center. In general, these patients required a total of 224 surgical procedures over an average of approximately three years after injury to achieve a successful outcome. Final limb function, however, was often impaired.

Adult↗
PubMed1989

Acoustic-phonetic characteristics of speech produced in noise and while wearing an oxygen mask.

The present study investigated changes in the prosodic and acoustic-phonetic features of isolated words by four male talkers speaking in quite and in pink noise at a level of 95 dB SPL. Speech samples were collected both with and without an oxygen mask. Changes in duration, fundamental frequency, total energy, and formant center frequency were analyzed. In addition to the expected changes of increased pitch and amplitude associated with speaking in noise without an oxygen mask, significant effects were found (particularly in the formant center frequencies) as a result of using the oxygen mask. When the oxygen mask was employed, no further significant changes were caused by adding noise to the speaking situation.

Humans↗
PubMed1989

Angiotensin-mediated renin suppression is altered in non-modulating hypertension.

Plasma renin activity (PRA) suppression by angiotensin II (Ang II), the "short feedback loop," has been shown to be blunted in essential hypertension. Non-modulators comprise 50% of normal- and high-renin essential hypertensive individuals and are defined by their abnormal adrenal and renal responses to infused Ang II. This study sought to determine if the abnormal Ang II suppression of PRA in essential hypertension is specific to non-modulators. We measured PRA suppression during infusion of Ang II in 22 normotensive and 32 hypertensive (16 modulators and 16 non-modulators) subjects. A significant correlation between basal PRA and the fall in PRA in response to Ang II infusion was seen in the normotensives (r = -0.934, p less than 0.001) and modulators (r = -0.831, p less than 0.001) but not in the non-modulators (r = -0.275, p = 0.304). However, after 3 days of converting enzyme inhibition therapy, the correlation between basal PRA and decrement in PRA was significant in the non-modulators (r = -0.762, p less than 0.01). Thus, the abnormal PRA suppression documented previously in hypertensive individuals is a defect specific to non-modulators and is corrected with converting enzyme inhibition therapy.

Adult↗
PubMed1989

A single dose of lithium carbonate acutely elevates intact parathyroid hormone levels in humans.

Hyperparathyroidism has been reported in patients receiving lithium therapy, and lithium alters calcium-regulated PTH release in vitro. Previous studies in vivo have used assays which measure fragments of PTH as well as the intact hormone. To determine if lithium acutely elevates intact PTH levels, we studied 9 subjects who received a single oral dose of lithium carbonate (600 mg). Serum levels of intact PTH, ionized calcium, and lithium were measured before, 2 and 14 h after the dose of lithium. PTH levels rose significantly 2 h following the dose of lithium (before 22 +/- 5.0, post 32 +/- 7.3 ng/l, p less than 0.02). PTH levels had returned to baseline at 14 h (22 +/- 3.8 ng/l). There were no significant changes in ionized calcium levels. Therefore, a single oral dose of lithium carbonate acutely elevates intact PTH values in human subjects.

Administration, Oral↗
PubMed1989

The use of quantitative bacterial counts in open fractures.

Late infections remain a significant complication in the treatment of open fractures, occurring in 2% to 25% of all open fractures. Recently there has been a trend toward early soft-tissue coverage of open fracture wounds. Quantitative bacterial counts have been used primarily by plastic surgeons to assess the viability of primary versus delayed wound closures. Quantitative bacterial counts were obtained in 52 consecutive open fractures in 50 patients to assess the correlation between quantitative bacterial counts and subsequent sepsis, to determine the effect of time to debridement on the quantitative bacterial count, and finally to review the bacteriology of open fractures. Forty-one of the 52 fractures had positive quantitative bacterial counts. Four of eight (50%) fractures with quantitative bacterial counts greater than 10(5) developed late sepsis, while only two of 44 (5%) with quantitative bacterial counts less than 10(5) or negative quantitative counts became infected. There was no correlation between time to debridement and quantitative bacterial count levels. A significant percentage of the positive quantitative bacterial counts were gram-negative organisms.

Adult↗
PubMed1989

Prosthetic usage following major lower extremity amputation.

There were 157 patients following major lower extremity amputation who were evaluated to determine functional prosthetic ambulation. Twenty-eight patients were evaluated in the amputee clinic and found not to be candidates for prosthetic fitting. Forty-one patients were fit with a prosthesis but did not become functional prosthetic ambulators. Eighty-eight patients became functional prosthetic ambulators. Of all above-the-knee amputees, 46% became functional prosthetic ambulators. Only 19% of bilateral lower extremity amputees became functional prosthetic ambulators. Of all below-the-knee amputees, 66% became functional ambulators. The presence of coronary artery disease decreased the ambulatory potential in above-the-knee or bilateral amputees but not in below-the-knee amputees. A screening method for elderly, dysvascular amputees should be instituted prior to prosthetic fitting.

Aged↗
PubMed1988

Abnormal regulation of adrenal angiotensin II receptors in spontaneously hypertensive rats.

The aldosterone response to angiotensin II is blunted in spontaneously hypertensive rats (SHR). To determine whether this blunting is due to a defect in angiotensin II receptors, we assessed angiotensin II binding to intact adrenal glomerulosa cells in SHR and normotensive Wistar-Kyoto rats (WKY) that had been fed high or low sodium diets before sacrifice. In rats on high salt intake, we observed no difference between the two strains in either receptor affinity (Kd = 1.0-1.2 nM) or binding capacity (36,000-38,000 receptors/cell). When sodium-restricted, WKY increased receptor content more than fourfold to 167,000 sites/cell. SHR increased receptor number to only 103,000 sites/cell, which was significantly (p less than 0.01) less than the WKY increase. The cause of the abnormal receptor regulation remains unclear. Two known receptor regulators, the plasma angiotensin II level and the state of potassium balance, were similar in the two strains. Our results suggest that the blunted aldosterone response to angiotensin previously reported in SHR is due to abnormal angiotensin receptor up-regulation in the adrenal gland in response to sodium restriction.

Adrenal Glands↗
PubMed1987

The results of quadricepsplasty on knee motion following femoral fractures.

Knee motion following femoral fractures is often less than satisfactory. Surgical procedures to increase knee motion are rarely done. This paper presents a series of nine patients who had severe femoral fractures, primarily in the distal third. Once union was obtained, all patients had knee flexion incompatible with normal gait (average 30.2 degrees). All patients underwent a quadricepsplasty at Rancho Los Amigos Medical Center. Eight of the nine achieved knee flexion allowing normal gait (average 78 degrees). This paper presents our indications, methods, results, and complications in performing quadricepsplasty to achieve knee flexion following femoral fractures.

Adult↗
PubMed1987

Chronic sepsis following intramedullary nailing of femoral fractures.

We reviewed 12 patients with chronic drainage after intramedullary nailing of a femoral shaft fracture. The fractures tended to be the result of high-speed trauma and were frequently comminuted. Six were open fractures and six were closed injuries. All but one had been managed initially with the open nailing technique, exposing the fracture site. In six cases we left the nail in place until bone union occurred, an average of 33 months after injury, removing the hardware thereafter. The remaining six patients, each with bone sequestra at the fracture site, underwent nail removal, debridement of nonviable bone, and external fixation followed by bone grafting; this group took 37 months to heal. There was one persistent nonunion in each group. Drainage did not cease in either group until the nail and all sequestra had been removed. There was an average of 4.3 cm of shortening, but no angulation greater than 10 degrees. Six patients were left with less than 45 degrees of knee flexion and only five had 100 degrees or more of knee flexion.

Adult↗
PubMed1987

Complications of surgically treated supracondylar fractures of the femur.

Surgical treatment of supracondylar fractures of the femur has become commonplace. A variety of surgical implants are available. In carefully chosen patients treated with appropriate surgical technique, early motion and good knee function can be obtained with open reduction and internal fixation. However, the morbidity (and mortality) are substantial following complications of open reduction and internal fixation of supracondylar fractures of the femur. We present a series of 30 consecutive patients referred to Rancho Los Amigos Medical Center for complications following open reduction and internal fixation of supracondylar femur fractures. Three patients with septic pseudarthrosis underwent above-knee amputations. Two of these three patients died of systemic sepsis. Fourteen additional patients were treated for nonunions, with 13 patients achieving union at an average time of 36.5 months from the date of injury. Six patients underwent quadricepsplasties for residual knee stiffness. Only 16 patients were returned to their preinjury ambulatory status.

Adult↗
PubMed1987

Changes in adrenal responsiveness and potassium balance with shifts in sodium intake.

Dietary sodium modulates the aldosterone response to angiotensin, but available evidence does not indicate whether there is a gradual change in adrenal responsiveness with intermediate sodium intakes or a sharp shift from a low to a high responsive level at some threshold sodium intake. Nine normal subjects received angiotensin II infusions while in balance on five levels of sodium intake over two orders of magnitude, 3 to 300 mEq sodium per day. Basal plasma renin activity, plasma aldosterone and plasma angiotensin II concentrations gradually fell as dietary sodium intake increased. The adrenal was quite sensitive to the state of sodium balance since a shift in sodium intake of as little as 20 mEq (e.g. 10 to 30 mEq/day) induced a significant change in basal plasma aldosterone. Adrenal responsiveness to infused angiotensin varied inversely with the log of urinary sodium excretion over the entire range of sodium intake, indicating that there is a gradual modulation of adrenal responsiveness with changes in dietary sodium. In addition, despite a constant dietary potassium intake, serum potassium gradually fell from 4.55 +/- .06 to 3.98 +/- .07 mEq/l, (P less than 0.02), as sodium intake increased, partly due to increased urinary potassium excretion (mean cumulative potassium loss of 129 mEq). Thus, changes in potassium balance may be important in modulating the sodium-associated variation in aldosterone secretion.

Adrenal Glands↗