Biomedical subjects

J M Lynch

Publications and source records attributed to J M Lynch.

At least 55 records · Page 3Linked to original sources

PubMed1998

The purification and characterization of a Trichoderma harzianum exochitinase.

A chitinolytic enzyme was purified from the culture filtrate of T. harzianum (T198) by precipitation with ammonium sulphate followed by affinity binding to swollen chitin and release with 10% (v/v) acetic acid. The molecular weight of the enzyme was calculated to be 28 and 27.5 kD by gel filtration chromatography and SDS-PAGE, respectively. The isoelectric point of the enzyme was 7.4. The pH optimum for activity was 3.5 and maximum activity was obtained at 50 degrees C. The enzyme displayed activity on a wide array of chitin substrates of more than two N-acetylglucosamine units in length. HPLC analysis of hydrolysis products demonstrated that the enzyme was an exochitinase releasing N-acetylglucosamine only.

Amino Acids↗

PubMed1998

The continuing problem of all-terrain vehicle injuries in children.

BACKGROUND: After the introduction of the all-terrain vehicle (ATV) in the United States in 1971, deaths and injuries in both adults and children rose dramatically. In 1988, the Consumer's Product Safety Commission (CPSC) and all manufacturers of ATVs signed legally binding "Consent Decrees," designed to decrease the number of ATV-related deaths and injuries, especially in children. METHODS: This report reviews retrospectively the mechanism of injury as well as the injuries in 51 children caused by ATV crashes during a 5-year period after the signing of the decrees. RESULTS: Data included age; sex; type of ATV (three or four wheel); position of the patient on the vehicle (driver or passenger); helmet usage; and mechanism of vehicular accident, including collision with a stationary or moving object, rollover, or fall from the vehicle. Mechanism data indicate loss of control of vehicle or fall from the vehicle as the most common cause of injury. Injury statistics included body regions and parts injured, injury severity score (ISS), and complications or disabilities resulting from injury. Mean ISS was 13.6 +/- 9.7 (range, 1 to 50). Eighteen patients (35%) had ISSs greater than 15. Helmets were worn by only 30% of patients. There were two deaths, and two patients suffered permanent paralysis. Orthopedic injuries were the most common injury and were of adult type with 61% classified as open or comminuted. CONCLUSIONS: The magnitude and severity of these injuries argue that this recreational vehicle is exceedingly dangerous for children. The consent decrees have had little effect on reducing the injuries in children from ATVs and should be reevaluated.

Accidents↗

PubMed1997

Creatine supplementation enhances muscular performance during high-intensity resistance exercise.

OBJECTIVE: This study was undertaken to investigate the influence of oral supplementation with creatine monohydrate on muscular performance during repeated sets of high-intensity resistance exercise. SUBJECTS/DESIGN: Fourteen active men were randomly assigned in a double-blind fashion to either a creatine group (n = 7) or a placebo group (n = 7). Both groups performed a bench press exercise protocol (5 sets to failure using each subject's predetermined 10-repetition maximum) and a jump squat exercise protocol (5 sets of 10 repetitions using 30% of each subject's 1-repetition maximum squat) on three different occasions (T1, T2, and T3) separated by 6 days. INTERVENTION: Before T1, both groups received no supplementation. From T1 to T2, both groups ingested placebo capsules. From T2 to T3, the creatine group ingested 25 g creatine monohydrate per day, and the placebo group ingested an equivalent amount of placebo. MAIN OUTCOME MEASURES: Total repetitions for each set of bench presses and peak power output for each set of jump squats were determined. Other measures included assessment of diet, body mass, skinfold thickness, and preexercise and 5-minute postexercise lactate concentrations. RESULTS: Lifting performance was not altered for either exercise protocol after ingestion of the placebos. Creatine supplementation resulted in a significant improvement in peak power output during all 5 sets of jump squats and a significant improvement in repetitions during all 5 sets of bench presses. After creatine supplementation, postexercise lactate concentrations were significantly higher after the bench press but not the jump squat. A significant increase in body mass of 1.4 kg (range = 0.0 to 2.7 kg) was observed after creatine ingestion. CONCLUSION: One week of creatine supplementation (25 g/day) enhances muscular performance during repeated sets of bench press and jump squat exercise.

Adult↗

PubMed1997

Computed tomography grade of splenic injury is predictive of the time required for radiographic healing.

It is largely unknown when a child who has suffered a splenic laceration can return to full unrestricted activity. The purpose of this prospective study is to establish whether the grade of splenic injury is predictive of the length of time required for radiographic healing, and to determine whether there are any adverse long-term sequelae after resumption of unlimited activity. Sixty-nine patients underwent successful nonoperative management (NOM) of computed tomography (CT)-documented splenic injury over a 4-year period. Fifty-eight patients completed follow-up. Mean age was 9.8 years (range, 1 to 17) and mean injury severity score (ISS) was 14.4 (range, 4 to 38). Mechanisms of injury were motor vehicle accident (n = 11), motor vehicle pedestrian (n = 5), falls (n = 13), bike crashes (n = 12), sports (n = 8), all-terrain vehicle (n = 4), and horse (n = 5). The CT-documented injury was identified by discharge ultrasound scan (US) in all cases. There were no long-term complications. Mean time to US healing in grade I (n = 9), II (n = 26), III (n = 19), IV (n = 4) injuries was 3.1, 8.2, 12.1, and 20.7 weeks, respectively. P values were significant (P < .01) in all cases when compared with the next lower injury grade. The time to radiographic healing is directly proportional to the severity of the splenic injury. There was excellent correlation between the initial CT scan and identification of the injury on the discharge US. No long-term complications leg, delayed splenic rupture, splenic pseudocyst) were seen in this study. Pediatric patients who have suffered splenic injury can safely return to full unrestricted activity when the US documents healing.

Adolescent↗

PubMed1997

Comparison of simultaneously obtained arterial and capillary blood gases in pediatric intensive care unit patients.

OBJECTIVE: To determine whether capillary blood gas measurements provide a clinically acceptable estimate of arterial pH, PCO2, and PO2. DESIGN: Prospective convenience sample. SETTING: Pediatric intensive care unit at a referral children's hospital. PATIENTS: Fifty children > 1 month of age with indwelling arterial catheters. INTERVENTIONS: A local anesthetic was applied to the third finger of the hand contralateral to a radial artery catheter. After 90 mins, simultaneous arterial and capillary blood gases were drawn. MEASUREMENTS AND MAIN RESULTS: Arterial and capillary pH, PcO2, and PO2 were measured. Heart rate and Wong/Baker faces score were noted before and during capillary blood gas collection to assess discomfort associated with blood collection. There was a strong correlation between capillary and arterial pH (r2 = .903, p < .0001). The relative average bias of the capillary pH was 0.009, with capillary lower than arterial and 95% limits of agreement of +/- 0.032. In all patients, the absolute value of the difference between arterial and capillary pH was < or = 0.05. There was a strong correlation between arterial and capillary PCO2 (r2 = .955, p < .0001). The relative average bias of the capillary PCO2 was 1.6 torr (0.21 kPa), with capillary higher than arterial and 95% limits of agreement of +/- 4.5 torr (+/- 0.6 kPa). In two of 50 patients, the absolute value of the difference between arterial and capillary PCO2 was > 6.5 torr (> 0.87 kPa). Despite a statistically significant correlation between capillary and arterial PO2 (r2 = .358, p < .0001), the absolute value of the difference between arterial and capillary PO2 was > 6.5 torr (> 0.87 kPa) in 42 of 50 patients. Pain, endotracheal intubation, vasoactive drips, or pharmacologic paralysis did not affect accuracy of the capillary pH or PCO2. CONCLUSIONS: Capillary blood gases accurately reflect arterial pH and PCO2 in most pediatric intensive care unit patients. Capillary samples did not significantly underestimate arterial hypercarbia or acidosis. This conservative reflection of metabolic status may be particularly useful in hemodynamically stable patients with mild-to-moderate lung disease.

Acidosis↗

PubMed1997

Single rope tree swing injuries among children.

OBJECTIVE: To examine the scope and severity of injuries sustained from falls from single rope tree swings among children. METHODS: Twenty-six children formed the basis of this retrospective study. Patients were divided into three groups based on the estimated distance of their fall (one, two, or three stories). Data were analyzed with respect to mechanism of injury, age, gender, length of hospital stay, injury severity score, number and type of injuries, and mortality. RESULTS: Eighteen patients fell from ropes, and 8 from vines (all onto packed dirt). Fourteen falls occurred from one story or less, 8 from two stories, and 4 from three stories. One death occurred from intracranial injury following a two-story fall. No difference in age, gender, injury severity score, or length of hospital stay with respect to the height of the fall was observed. Falls from lower heights resulted in equally severe injuries as falls from higher heights. Overall, head trauma was the most common injury (58%) followed by long bone fractures (42%), axial skeletal fractures (23%), and intra-abdominal visceral injuries (8%). CONCLUSIONS: The present study demonstrated that recreational single rope tree swing injuries among children resulted in significant morbidity regardless of the height of the fall. This activity carries a substantial risk for serious injury. The mechanism of injury, clinical data, and the importance of medical awareness and patient education are emphasized.

Abdominal Injuries↗

PubMed1997

Ad libitum suckling by an unrelated calf in the presence or absence of a cow's own calf prolongs postpartum anovulation.

Our objective was to determine whether onset of first postpartum ovulation would be altered in suckled cows nursing an unrelated calf in the presence or absence of their own nonsuckling calf. In a 2-yr study, Angus x Hereford cows were assigned randomly to five treatments between d 13 and 18 postpartum for 4 wk: 1) own calf was weaned (OCW, n = 9); 2) own calf was present continuously (OCP, n = 12); 3) own calf was present continuously but restricted from udder contact (OCR, n = 9); 4) unrelated calf was present continuously after own calf was removed (UCP, n = 10); and 5) unrelated calf was present continuously and own calf was present but restricted as in the OCR treatment (OCR + UCP, n = 10). Interval to the first increase in progesterone (ovulation) was less (P < .05) in OCW (14.7 +/- 3.4 d) and OCR (19.9 +/- 3.4 d) than in the OCP (35.0 +/- 2.9 d), UCP (38.0 +/- 3.4 d), and OCR + UCP (37.6 +/- 3.4 d) treatments. The OCW cows showed no maternal bond with their own calves after 4 wk of treatment, whereas OCR, OCP, and OCR + UCP cows were bonded to their own natural calves. Cows in the UCP treatment, suckled by unrelated calves, formed new maternal bonds with those calves, resulting in prolonged anovulation. Further, OCR + UCP cows had prolonged anovulation because maternal bonds were maintained with their own restricted calves while milk was removed by unrelated calves. We conclude that milk removal preceded by a continuously reinforced cow-calf bond (original or reestablished) is essential to prolong anovulation in beef cows.

Analysis of Variance↗

PubMed1997

Influence of timing of gain on growth and reproductive performance of beef replacement heifers.

Our objective was to determine whether beef heifers could be developed by delaying the majority of weight gain until the last third of the developmental period before the onset of the breeding season. Spring-born Angus x Hereford heifers were used in each of two consecutive years and were allotted at weaning to gain either .45 kg/d for the entire developmental period (yr 1 = 159 d, n = 40; yr 2 = 168 d, n = 40; EVENGAIN) or to gain .11 kg/d from d 0 to 112, followed by .91 kg/d from d 112 to 159 (yr 1, n = 40) or d 168 (yr 2, n = 40; LATEGAIN). Body weights and condition scores were determined at d 0, 112, and 159 (yr 1) or d 0, 112, and 168 (yr 2). Heifers were subjected to a 60-d breeding season. Frame scores and pelvic areas were determined at the conclusion of the breeding season. Actual daily gains for EVENGAIN heifers for yr 1 and yr 2 were .60 and .51 kg/d, respectively. LATEGAIN heifers gained .25 and .05 kg/d during the restricted phases from d 0 to 112, followed by 1.14 and 1.32 kg/d during the accelerated growth phases for yr 1 and 2, respectively. Body weight at the onset of the breeding season and weight at puberty were not different between treatments in either year. Age at puberty did not differ in yr 1, but, age at puberty in yr 2 was delayed (P < .01) in LATEGAIN (406.9 d) compared to EVENGAIN (386.3 d) heifers. The LATEGAIN and EVENGAIN heifers had similar pelvic areas, frame scores, and body condition scores in each year. First-service conception rates of both groups were similar in yr 1 (55.5 vs 55.3%). In yr 2, LATEGAIN heifers tended (P = .18) to have an increase in first-service conception rate compared to EVENGAIN heifers (71.1 vs 56.4%). No treatment differences occurred in either average age of conception or overall pregnancy rates at the conclusion of the breeding season for either year. The LATEGAIN heifers were developed to a similar BW on 12 (P < .01) and 2.5% (not statistically significant) less feed for yr 1 and 2, respectively, compared to EVENGAIN heifers. We interpret these data to indicate that delaying the majority of weight gain until late in heifer development may decrease costs without detrimental effects on reproductive performance.

Analysis of Variance↗

PubMed1997

Influence of milking three times a day on milk quality.

Lactations were divided into three periods: early (1 to 99 d), mid (100 to 199 d), and late (200 to 299 d). One hundred Holsteins were randomly split into four groups that were balanced for parity. Groups 222 and 333 were milked twice and three times a day, respectively, throughout lactation. Group 233 was switched from twice to three times daily milking at 100 d, and group 223 was switched at 200 d. Compared with group 222, milk yield for group 333 increased by 10.4%, and fat and protein yields increased by 4.7 and 7.3%, respectively. Mean milk SCC for all groups was < 175,000 cells/ml within each lactation period. The percentage of CP was lower for cows milked three times a day than for cows milked twice a day during each stage of lactation (early, 2.78 and 2.91; mid, 3.08 and 3.19; and late, 3.16 and 3.28, respectively). Casein as a percentage of CP was significantly higher for cows milked three times a day during midlactation. The acid degree values (milliequivalents of FFA/ 100 g of fat) were significantly higher for milk from cows milked three times a day than for cows milked twice a day during early and midlactation, (early, 0.75 and 0.55; mid, 0.82 and 0.61; and late, 0.88 and 0.75, respectively). No differences were detected in milk flavor or plasmin activity because of milking frequency. Casein as a percentage of CP decreased, and plasmin activity increased, as parity and stage of lactation increased.

Animals↗

PubMed1996

The effects of plasma cortisol elevation on total and differential leukocyte counts in response to heavy-resistance exercise.

The purpose of this study was to examine the impact of heavy-resistance exercise-induced elevations of plasma cortisol on circulating leukocyte counts. Nine healthy, recreationally weight-trained men volunteered for this investigation. Two exercise protocols were employed. Protocol 1 (P-1) consisted of eight sets of ten-repetition maximum leg-press exercise with 1-min rest periods between sets. Protocol 2 (P-2) was identical except for 3-min rest periods. A non-exercise protocol was used as a control treatment (C). Venous blood samples, heart rates and ratings of perceived exertion were obtained pre-, mid- and 5 min post-exercise. In order to examine the maximal influence of cortisol on leukocyte counts, we placed the subject's highest magnitude of cortisol change in response to one of the heavy-resistance exercise protocols in what we designated as the response protocol (R) and the other value was placed into what was designated as the non-response protocol (NR) for analysis. Significant increases in cortisol occurred from pre- to post-exercise for P-1 [mean (SD) 241.4 (25.0) to 302.0 (60.0)nmol . 1(-1)] and in the R conditions pre- to mid- and pre- to post-exercise [218.0(0.0) to 302.4 (37.1) to 326.8 (51.9)nmol . 1(-1)]. No significant changes in cortisol occurred for P-2, NR or the control conditions. Significant increases in total leukocyte counts occurred from pre- to mid- and pre- to post-exercise both for R [5.6 (0.4) to 7.4 (0.3) to 7.3 (0.3) cells . 10(9) . 1(-1)] and NR [5.7 (0.3) to 6.9 (0.4) to 7.1(0.4) cells . 10(9) . l(-1)]. No significant changes in differential leukocyte counts occurred. In addition, no significant correlations between cortisol and total or differential leukocyte counts were observed. These data indicate that acute increases in total leukocytes along with no changes in differential leukocyte counts can occur in response to heavy-resistance exercise that does not significantly elevate plasma cortisol concentrations.

Adult↗

PubMed1996

Intestinal stricture following seat belt injury in children.

The most commonly reported intestinal injury from seat belts in children is perforation. A rarely reported late sequela following this type of injury is posttraumatic intestinal stricture (PTIS). A review of the literature reveals a common clinical pattern of presentation in children and adults but an apparent difference in the pathophysiologic mechanism between the pediatric and adult patient. Recently, we treated two children with PTIS. Each case is discussed, and a pathophysiological mechanism for this injury in children is proposed. Recommendations are made for the evaluation and treatment of these uncommon complications of seat belt-related blunt intestinal injury.

Adult↗

PubMed1996

Hemodynamic significance of pediatric femur fractures.

PURPOSE: To determine whether hemodynamically significant bleeding occurs after pediatric femur fractures. METHOD: A retrospective chart review was performed; demographic and injury data were collected for all patients with the diagnosis of femur fracture over a 30-month period at a level/ pediatric trauma center. Included were patients with multisystem injury and patients with femur fractures as the only injury. The incidence of hemodynamic insufficiency, the reasons for and timing of transfusions, and the changes in hematocrit levels over time were evaluated. RESULTS: One hundred seventy-eight children were identified (182 femur fractures). There were 116 boys and 62 girls, and the mean age was 6.04 +/- 4.5 years (range, 1 month to 19 years). The mechanisms of injury included falls (46), pedestrian/ motor vehicle accidents (43), motor vehicle crashes (19), sports accidents (22), abuse (10), and miscellaneous (38). The mean Injury Severity Score (ISS) was 5.88 +/- 3.93 (range, 4 to 29). There were no deaths. The length of hospital stay was 8.13 +/- 9.37 days (range, 1 to 43 days). Prehospital treatment included early immobilization. Fracture treatment was according to recognized orthopedic techniques based on age, size, and fracture configuration. The mean hematocrit in the emergency department was 34% +/- 3.5% (range, 27.8% to 44.4%) and 32% +/- 6.6% (range, 16.9% to 47.8%) at 24 hours. 67 patients (38%) suffered multiple injuries. Mean ISS for this group was 9.4 +/- 5.0 (range, 5 to 29). Four patients had hemodynamic insufficiency at the time of admission. All were in the multiple-injury group Seven of these 67 patients (10%) required transfusion-three in the first 24 hours (two in the emergency department [associated with severe facial/scalp bleeding] and one in the operating room [associated with severe liver injury]) and four after the first 24 hours (three associated with intraoperative orthopedic procedures and one with a hemothorax). The mean age of those who underwent transfusion was 8.29 +/- 4.79 years, and their mean ISS was 13.71 +/- 4.61. All patients who required transfusion had been injured in motor vehicle crashes or in pedestrian/motor vehicle accidents. One hundred eleven children had isolated closed femur fractures. No patient in this group had evidence of hemodynamic insufficiency or required transfusion. The initial mean hematocrit was 34.5% +/- 2.7%, and the mean 24-hour hematocrit was 34.6% +/- 3.2%. We found that (1) no child with an isolated closed femur fracture had evidence of hemodynamic instability, or showed significant blood loss as evidenced by a decreasing hematocrit at 24 hours, and (2) in this series, evidence of hemodynamic insufficiency and/or the need for transfusion was found only in multiply injured children. CONCLUSION: Hemodynamic instability or evidence of a declining hematocrit in the child should not be attributed to a closed femur fracture and that other sources of blood loss must be found.

Anemia↗

PubMed1996

Inhaled nitric oxide in children with severe lung disease: results of acute and prolonged therapy with two concentrations.

OBJECTIVES: To evaluate the acute effects of 11 and 60 parts per million (ppm) inhaled nitric oxide on the pulmonary vascular resistance and systemic oxygenation of children with severe lung disease, and to compare the outcome of prolonged therapy with approximately 10 and 40 ppm inhaled nitric oxide. DESIGN: Prospective, randomized study. SETTING: A 26-bed pediatric intensive care unit in a tertiary children's hospital. PATIENTS: Nineteen patients (median age 11 yrs, range 7 months to 16 yrs) with acute bilateral lung disease requiring a positive end-expiratory pressure (PEEP) of > 6 cm H2O and an FIO2 of > 0.5 for > 12 hrs were treated with inhaled nitric oxide. One patient was treated twice during the same hospitalization. INTERVENTIONS: Acute hemodynamic and blood gas effects of 11 and 60 ppm inhaled nitric oxide were studied, while delivering these concentrations in random order for intervals of 20 to 30 mins. Each interval was preceded by an interval of 20 to 30 mins without nitric oxide. Patients were then randomized and treated for a prolonged period with approximately 10 or 40 ppm inhaled nitric oxide independent of their initial acute responses to 11 and 60 ppm. Nitric oxide was discontinued when ventilatory support was decreased to a PEEP of < or = 6 cm H2O and an FIO2 of < or = 0.5. MEASUREMENTS AND MAIN RESULTS: Inhaled nitric oxide selectively decreased pulmonary vascular resistance and improved systemic oxygenation. Acute hemodynamic and blood gas effects of 11 and 60 ppm nitric oxide were similar. Systemic oxygenation improved to a greater extent in patients with radiographic evidence of residual aerated lung regions than in patients with diffuse bilateral lung disease. Maximum methemoglobin concentrations were greater in patients treated for a prolonged period with 40 ppm nitric oxide. The mortality and duration of therapy were similar for patients treated with 10 and 40 ppm inhaled nitric oxide. CONCLUSIONS: Pulmonary vascular resistance and systemic oxygenation are acutely improved to a similar extent by 11 and 60 ppm inhaled nitric oxide, and concentrations in excess of 10 ppm are probably not needed for prolonged therapy of children with severe lung disease.

Administration, Inhalation↗

PubMed1996

Is computed tomography a useful adjunct to the clinical examination for the diagnosis of pediatric gastrointestinal perforation from blunt abdominal trauma in children?

Perforations of the gastrointestinal (GI) tract, compared to solid organ injuries, are a relatively infrequent sequela of blunt abdominal trauma in children. The purpose of this study is to review retrospectively the diagnostic modalities used in 30 children with proven traumatic intestinal perforations treated at one institution. Since computed tomography with intravenous and oral GI contrast is commonly used in the diagnosis of suspected solid organ injury from blunt abdominal trauma, we evaluated retrospectively the computed tomographic (CT) scan findings in these children in an attempt to accurately predict or suggest GI perforation. Between January 1987 and December 1993, 5,795 children were admitted. Three hundred fifty suffered blunt abdominal trauma of which 30 patients (8.5%) required surgery for a GI perforation and formed the basis for this study. Data collected were mechanisms of injury, results of admission and serial clinical examinations, results of radiologic imaging, associated injuries, operative findings, and outcome. Follow-up was obtained on all patients and averaged 2.5 years. Blows to the abdomen (handlebars, cars, kicks) were the most common cause of perforation, followed by seatbelt injuries. Eleven patients underwent immediate laparotomy an average of 0.75 hours after admission. The indication for surgery was shock (three), clinically apparent peritonitis (five), and free air on plain abdominal radiograph (three). Nineteen patients underwent "later" laparotomy, an average of 3.4 hours after admission, all because of the eventual development of peritonitis. Retrospective review of these CT scans revealed free air anterior to the liver in three, and the remaining 16 had CT findings suggestive of GI injury such as free fluid, focal fluid-filled thick-walled bowel loops, and mesenteric infiltration. There were five (26%) false negative CT scans performed an average of 5.0 hours after injury. We believe serial physical examinations are the gold standard for diagnosing pediatric GI perforation from blunt abdominal trauma. The CT scan may be a useful adjunct to the diagnosis of an intestinal perforation in patients who have no immediate indication for surgery. Presently, the only CT finding that is an absolute indication for laparotomy is free air (in the absence of pulmonary/mediastinal injury or barotrauma). The other CT "findings" need to be validated prospectively.

Abdominal Injuries↗

PubMed1996

Direct injury to the cervical spine of a child by a lap-shoulder belt resulting in quadriplegia: case report.

Most pediatric cervical spine injuries from seat-belt restraints result from hyperflexion of the neck without direct injury to the spine from the restraining device. We report what we believe to be the first case of direct injury to the cervical spine by the shoulder component of a lap-shoulder seat belt. This resulted in quadriplegia. The mechanism of injury and recommendations to obviate such injuries are discussed.

Accidents, Traffic↗

PubMed1996

Geometric morphometrics in primatology: craniofacial variation in Homo sapiens and Pan troglodytes.

Traditionally, morphometric studies have relied on statistical analysis of distances, angles or ratios to investigate morphometric variation among taxa. Recently, geometric techniques have been developed for the direct analysis of landmark data. In this paper, we offer a summary (with examples) of three of these newer techniques, namely shape coordinate, thin-plate spline and relative warp analyses. Shape coordinate analysis detected significant craniofacial variation between 4 modern human populations, with African and Australian Aboriginal specimens being relatively prognathous compared with their Eurasian counterparts. In addition, the Australian specimens exhibited greater basicranial flexion than all other samples. The observed relationships between size and craniofacial shape were weak. The decomposition of shape variation into affine and non-affine components is illustrated via a thin-plate spline analysis of Homo and Pan cranial landmarks. We note differences between Homo and Pan in the degree of prognathism and basicranial flexion and the position and orientation of the foramen magnum. We compare these results with previous studies of these features in higher primates and discuss the utility of geometric morphometrics as a tool in primatology and physical anthropology. We conclude that many studies of morphological variation, both within and between taxa, would benefit from the graphical nature of these techniques.

Africa↗

PubMed1996

Acute response to inhaled nitric oxide in newborns with respiratory failure and pulmonary hypertension.

OBJECTIVE: Systemic oxygenation is improved by inhaled nitric oxide therapy in some newborns with respiratory failure and pulmonary hypertension. Our results with inhaled nitric oxide were reviewed to determine factors associated with an acute improvement in systemic oxygenation. METHODS: Newborns with oxygenation indices of 25 to 40 were prospectively randomized to receive conventional therapy with or without 20 ppm inhaled nitric oxide. All newborns with oxygenation indices greater than 40 were treated with inhaled nitric oxide. Hemodynamic, blood gas, and Doppler ultrasound measurements were performed before and after 30 to 60 minutes of observation or therapy. The severity of lung disease was classified by the chest radiograph as: (1) normal or focal disease; (2) moderate diffuse disease-diffuse lung disease with well-defined heart borders; or (3) severe diffuse disease-diffuse lung opacification with indistinct heart borders. RESULTS: Heart rate, blood pressure, and ductal diameters did not change. Blood gases and ductal shunting acutely improved only in patients treated with inhaled nitric oxide. Patients with normal lung fields or focal disease had the greatest degree of improvement in systemic oxygenation. Changes in oxygenation were not influenced by gestational age, baseline blood gases, the proportion of right-to-left ductal shunting, prior treatment with a surfactant, or the use of conventional or high-frequency jet ventilation. Collectively, blood gases and ductal shunting did not improve with inhaled nitric oxide in patients with lung hypoplasia or severe diffuse lung disease. Sustained improvement in oxygenation occurred in 87% of patients with oxygenation indices greater than 40 in whom oxygenation indices less than 40 acutely developed after exposure to nitric oxide, whereas 90% of patients in whom oxygenation indices less than 40 did not acutely develop were treated with extracorporeal membrane oxygenation or ultimately died. CONCLUSIONS: Inhaled nitric oxide acutely improves systemic oxygenation in many newborns with respiratory failure and pulmonary hypertension. The diagnosis and chest radiograph are helpful in identifying patients who will have favorable acute responses to therapy. In patients with severe hypoxemia, the need for invasive support with extracorporeal membrane oxygenation may be determined by an acute trial of inhaled nitric oxide.

Acute Disease↗

PubMed1996

High-frequency jet ventilation in the pediatric intensive care unit.

Scientific data and anecdote on the utility of HFJV in children remain divergent. There seems to be some evidence that ventilation and oxygenation in critically ill patients can sometimes be achieved at lower peak airway pressures and tidal volumes. There is also growing consensus that HFJV may be a superior ventilatory technique for patients with air leak syndrome. However, conclusive evidence of the effect of this technology on overall survival, length of ventilation, or even resource consumption remains illusive. Until such time, a general recommendation for the use of HFJV in pediatric patients is not possible.

Adolescent↗